diff --git a/audio/softsynth/mt32.cpp b/audio/softsynth/mt32.cpp
index 11183058bdc..7b09e286501 100644
--- a/audio/softsynth/mt32.cpp
+++ b/audio/softsynth/mt32.cpp
@@ -77,7 +77,7 @@ public:
 		error("MT32emu: Init Error - Missing PCM ROM image");
 	}
 	void showLCDMessage(const char *message) {
-		Common::OSDMessageQueue::instance().addMessage(Common::convertToU32String(message));
+		Common::OSDMessageQueue::instance().addMessage(Common::U32String(message));
 	}
 
 	// Unused callbacks
diff --git a/backends/cloud/storage.cpp b/backends/cloud/storage.cpp
index 25c623e416d..76b6a241bb9 100644
--- a/backends/cloud/storage.cpp
+++ b/backends/cloud/storage.cpp
@@ -345,9 +345,7 @@ void Storage::directoryDownloadedCallback(FileArrayResponse response) {
 
 	Common::U32String message;
 	if (response.value.size()) {
-		message = Common::U32String::format(
-			_("Download complete.\nFailed to download %u files."),
-			response.value.size());
+		message = Common::U32String::format(_("Download complete.\nFailed to download %u files."), response.value.size());
 	} else {
 		message = _("Download complete.");
 	}
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 4445a2c6022..ecc6950cb36 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -2549,10 +2549,7 @@ bool SurfaceSdlGraphicsManager::notifyEvent(const Common::Event &event) {
 		endGFXTransaction();
 
 #ifdef USE_OSD
-		Common::U32String message = Common::String::format("%s: %s",
-		                                                _("Stretch mode").encode().c_str(),
-		                                                _(s_supportedStretchModes[index].description).encode().c_str()
-		);
+		Common::U32String message = _("Stretch mode") + Common::U32String(": ") + _(s_supportedStretchModes[index].description);
 		displayMessageOnOSD(message);
 #endif
 		_forceRedraw = true;
diff --git a/backends/keymapper/keymap.cpp b/backends/keymapper/keymap.cpp
index c86a982abb0..5a8f9f820df 100644
--- a/backends/keymapper/keymap.cpp
+++ b/backends/keymapper/keymap.cpp
@@ -44,6 +44,10 @@ Keymap::Keymap(KeymapType type, const String &id, const U32String &description)
 
 }
 
+Keymap::Keymap(KeymapType type, const String &id, const String &description) {
+	Keymap(type, id, U32String(description));
+}
+
 Keymap::~Keymap() {
 	for (ActionArray::iterator it = _actions.begin(); it != _actions.end(); ++it)
 		delete *it;
diff --git a/backends/keymapper/keymap.h b/backends/keymapper/keymap.h
index 3fca37873cc..e5c1c4d4aae 100644
--- a/backends/keymapper/keymap.h
+++ b/backends/keymapper/keymap.h
@@ -81,6 +81,7 @@ public:
 	typedef Array<Action *> ActionArray;
 
 	Keymap(KeymapType type, const String &id, const U32String &description);
+	Keymap(KeymapType type, const String &id, const String &description);
 	~Keymap();
 	void setConfigDomain(ConfigManager::Domain *configDomain);
 	void setHardwareInputs(HardwareInputSet *hardwareInputSet);
diff --git a/backends/text-to-speech/linux/linux-text-to-speech.cpp b/backends/text-to-speech/linux/linux-text-to-speech.cpp
index 8ff00047523..a7777f1a500 100644
--- a/backends/text-to-speech/linux/linux-text-to-speech.cpp
+++ b/backends/text-to-speech/linux/linux-text-to-speech.cpp
@@ -194,7 +194,7 @@ bool SpeechDispatcherManager::say(const Common::U32String &str, Action action, C
 		return true;
 	}
 
-	Common::String strUtf8 = str.encode();;
+	Common::String strUtf8 = str.encode();
 
 	if (!_speechQueue.empty() && action == INTERRUPT_NO_REPEAT &&
 			_speechQueue.front() == strUtf8 && isSpeaking()) {
diff --git a/backends/text-to-speech/windows/windows-text-to-speech.cpp b/backends/text-to-speech/windows/windows-text-to-speech.cpp
index d52014b3db7..80947cdfc4c 100644
--- a/backends/text-to-speech/windows/windows-text-to-speech.cpp
+++ b/backends/text-to-speech/windows/windows-text-to-speech.cpp
@@ -246,6 +246,10 @@ bool WindowsTextToSpeechManager::say(const Common::U32String &str, Action action
 	return false;
 }
 
+bool WindowsTextToSpeechManager::say(const Common::String &str, Action action, Common::String charset) {
+	return say(Common::U32String(str), action, charset);
+}
+
 bool WindowsTextToSpeechManager::stop() {
 	if (_speechState == BROKEN || _speechState == NO_VOICE)
 		return true;
diff --git a/backends/text-to-speech/windows/windows-text-to-speech.h b/backends/text-to-speech/windows/windows-text-to-speech.h
index ac0906117a0..00dabb7fe6d 100644
--- a/backends/text-to-speech/windows/windows-text-to-speech.h
+++ b/backends/text-to-speech/windows/windows-text-to-speech.h
@@ -53,6 +53,7 @@ public:
 	virtual ~WindowsTextToSpeechManager() override;
 
 	virtual bool say(const Common::U32String &str, Action action, Common::String charset = "") override;
+	virtual bool say(const Common::String &str, Action action, Common::String charset = "") override;
 
 	virtual bool stop() override;
 	virtual bool pause() override;
diff --git a/base/main.cpp b/base/main.cpp
index be3f5190d08..e378887f82c 100644
--- a/base/main.cpp
+++ b/base/main.cpp
@@ -260,7 +260,7 @@ static Common::Error runGame(const Plugin *plugin, OSystem &system, const Common
 		if (token.equalsIgnoreCase("all"))
 			DebugMan.enableAllDebugChannels();
 		else if (!DebugMan.enableDebugChannel(token))
-			warning(Common::convertFromU32String(_("Engine does not support debug level '%s'")).c_str(), token.c_str());
+			warning("Engine does not support debug level '%s'", token.c_str());
 	}
 
 #ifdef USE_TRANSLATION
diff --git a/common/text-to-speech.h b/common/text-to-speech.h
index 62aa953bf78..2e391152426 100644
--- a/common/text-to-speech.h
+++ b/common/text-to-speech.h
@@ -159,6 +159,7 @@ public:
 	 *        encoding used for the GUI.
 	 */
 	bool say(const U32String &str, String charset = "") { return say(str, INTERRUPT_NO_REPEAT, charset); }
+	bool say(const String &str, String charset = "") { return say(U32String(str), charset); }
 
 	/**
 	 * Says the given string
@@ -179,6 +180,7 @@ public:
 	 *        encoding used for the GUI.
 	 */
 	virtual bool say(const U32String &str, Action action, String charset = "") { return false; }
+	virtual bool say(const String &str, Action action, String charset = "") { return false; }
 
 	/**
 	 * Stops the speech
diff --git a/engines/agi/detection.cpp b/engines/agi/detection.cpp
index 3cf0fd81d76..e897e1258b2 100644
--- a/engines/agi/detection.cpp
+++ b/engines/agi/detection.cpp
@@ -332,7 +332,7 @@ SaveStateList AgiMetaEngine::listSaves(const char *target) const {
 
 				delete in;
 
-				saveList.push_back(SaveStateDescriptor(slotNr, Common::U32String(description)));
+				saveList.push_back(SaveStateDescriptor(slotNr, description));
 			}
 		}
 	}
@@ -375,11 +375,11 @@ SaveStateDescriptor AgiMetaEngine::querySaveMetaInfos(const char *target, int sl
 			// broken description, ignore it
 			delete in;
 
-			SaveStateDescriptor descriptor(slotNr, Common::U32String("[broken saved game]"));
+			SaveStateDescriptor descriptor(slotNr, "[broken saved game]");
 			return descriptor;
 		}
 
-		SaveStateDescriptor descriptor(slotNr, Common::U32String(description));
+		SaveStateDescriptor descriptor(slotNr, description);
 
 		// Do not allow save slot 0 (used for auto-saving) to be deleted or
 		// overwritten.
diff --git a/engines/agi/saveload.cpp b/engines/agi/saveload.cpp
index f02fadd55f3..77637846d20 100644
--- a/engines/agi/saveload.cpp
+++ b/engines/agi/saveload.cpp
@@ -767,7 +767,7 @@ int AgiEngine::scummVMSaveLoadDialog(bool isSave) {
 		}
 
 		if (desc.size() > 28)
-			desc = Common::U32String(desc.encode().c_str(), 28);
+			desc = Common::U32String(desc.begin(), desc.begin() + 28);
 	} else {
 		dialog = new GUI::SaveLoadChooser(_("Restore game:"), _("Restore"), false);
 		slot = dialog->runModalWithCurrentTarget();
diff --git a/engines/agos/midi.cpp b/engines/agos/midi.cpp
index 1811b8e3fad..34c7634d94e 100644
--- a/engines/agos/midi.cpp
+++ b/engines/agos/midi.cpp
@@ -37,6 +37,7 @@
 
 // PKWARE data compression library decompressor required for Simon 2
 #include "common/dcl.h"
+#include "common/translation.h"
 
 #include "gui/message.h"
 
@@ -139,12 +140,12 @@ int MidiPlayer::open(int gameType, bool isDemo) {
 		case MT_GM:
 			if (!ConfMan.getBool("native_mt32")) {
 				// Not a real MT32 / no MUNT
-				::GUI::MessageDialog dialog(Common::convertToU32String((
+				::GUI::MessageDialog dialog(_(
 											"You appear to be using a General MIDI device,\n"
 											"but your game only supports Roland MT32 MIDI.\n"
 											"We try to map the Roland MT32 instruments to\n"
 											"General MIDI ones. It is still possible that\n"
-											"some tracks sound incorrect.")));
+											"some tracks sound incorrect."));
 				dialog.runModal();
 			}
 			// Switch to MT32 driver in any case
diff --git a/engines/agos/saveload.cpp b/engines/agos/saveload.cpp
index 44208ff782d..d89d8f5ec3c 100644
--- a/engines/agos/saveload.cpp
+++ b/engines/agos/saveload.cpp
@@ -134,7 +134,7 @@ void AGOSEngine::quickLoadOrSave() {
 	if ((getGameType() == GType_SIMON2 && _boxStarHeight == 200) ||
 		(getGameType() == GType_SIMON1 && (getFeatures() & GF_DEMO)) ||
 		_mouseHideCount || _showPreposition) {
-		buf = Common::String::format("Quick load or save game isn't supported in this location");
+		buf = Common::U32String::format(_("Quick load or save game isn't supported in this location"));
 		GUI::MessageDialog dialog(buf);
 		dialog.runModal();
 		return;
diff --git a/engines/bbvs/dialogs.cpp b/engines/bbvs/dialogs.cpp
index 9f22c26c46d..c7afb748c26 100644
--- a/engines/bbvs/dialogs.cpp
+++ b/engines/bbvs/dialogs.cpp
@@ -192,7 +192,7 @@ void MainMenu::gotoMenuScreen(int screen) {
 		} else {
 			btn = &kMenuButtons[screen * 5 + i];
 		}
-		_buttons[i]->setLabel(Common::U32String(btn->label));
+		_buttons[i]->setLabel(btn->label);
 		_buttons[i]->setCmd(btn->cmd);
 		_buttons[i]->setEnabled(btn->cmd != 0);
 	}
diff --git a/engines/cge/cge.cpp b/engines/cge/cge.cpp
index 5574c8b16e5..814d1c2dbc7 100644
--- a/engines/cge/cge.cpp
+++ b/engines/cge/cge.cpp
@@ -225,7 +225,7 @@ Common::Error CGEEngine::run() {
 
 	// If game is finished, display ending message
 	if (_flag[3]) {
-		Common::U32String msg = Common::U32String(_text->getText(kSayTheEnd));
+		Common::String msg = Common::String(_text->getText(kSayTheEnd));
 		if (!msg.empty()) {
 			g_system->delayMillis(10);
 			GUI::MessageDialog dialog(msg);
diff --git a/engines/dialogs.cpp b/engines/dialogs.cpp
index efb4c6974cd..edb3ea98f83 100644
--- a/engines/dialogs.cpp
+++ b/engines/dialogs.cpp
@@ -214,9 +214,9 @@ void MainMenuDialog::save() {
 
 		Common::Error status = _engine->saveGameState(slot, Common::convertFromU32String(result));
 		if (status.getCode() != Common::kNoError) {
-			Common::U32String failMessage = Common::U32String::format(_("Failed to save game (%s)! "),
+			Common::U32String failMessage = Common::U32String::format(_("Failed to save game (%s)! "
 				  "Please consult the README for basic information, and for "
-				  "instructions on how to obtain further assistance.");
+				  "instructions on how to obtain further assistance."), status.getDesc().c_str());
 			GUI::MessageDialog dialog(failMessage);
 			dialog.runModal();
 		}
diff --git a/engines/drascula/drascula.cpp b/engines/drascula/drascula.cpp
index e695cc146d6..64d5f2868da 100644
--- a/engines/drascula/drascula.cpp
+++ b/engines/drascula/drascula.cpp
@@ -930,7 +930,7 @@ bool DrasculaEngine::loadDrasculaDat() {
 	if (!in.isOpen()) {
 		Common::U32String errorMessage = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
 		GUIErrorMessage(errorMessage);
-		warning("%s", errorMessage.encode().c_str());
+		warning("Unable to locate the '%s' engine data file.", filename.c_str());
 
 		return false;
 	}
@@ -944,7 +944,7 @@ bool DrasculaEngine::loadDrasculaDat() {
 	if (strcmp(buf, "DRASCULA") != 0) {
 		Common::U32String errorMessage = Common::U32String::format(_("The '%s' engine data file is corrupt."), filename.c_str());
 		GUIErrorMessage(errorMessage);
-		warning("%s", errorMessage.encode().c_str());
+		warning("The '%s' engine data file is corrupt.", filename.c_str());
 
 		return false;
 	}
@@ -956,7 +956,8 @@ bool DrasculaEngine::loadDrasculaDat() {
 			_("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d."),
 			filename.c_str(), DRASCULA_DAT_VER, 0, ver, 0);
 		GUIErrorMessage(errorMessage);
-		warning("%s", errorMessage.encode().c_str());
+		warning("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d.",
+			filename.c_str(), DRASCULA_DAT_VER, 0, ver, 0);
 
 		return false;
 	}
diff --git a/engines/engine.cpp b/engines/engine.cpp
index 0c606061faa..4fb538f6f27 100644
--- a/engines/engine.cpp
+++ b/engines/engine.cpp
@@ -320,7 +320,7 @@ void initGraphics(int width, int height, const Graphics::PixelFormat *format) {
 			_("Could not switch to resolution '%dx%d'."), width, height);
 
 		GUIErrorMessage(message);
-		error("%s", message.encode().c_str());
+		error("Could not switch to resolution '%dx%d'.", width, height);
 	}
 
 	// Just show warnings then these occur:
@@ -335,8 +335,7 @@ void initGraphics(int width, int height, const Graphics::PixelFormat *format) {
 
 	if (gfxError & OSystem::kTransactionModeSwitchFailed) {
 		Common::U32String message;
-		message = Common::U32String::format(
-			_("Could not switch to video mode '%s'."), ConfMan.get("gfx_mode").c_str());
+		message = Common::U32String::format(_("Could not switch to video mode '%s'."), ConfMan.get("gfx_mode").c_str());
 
 		GUI::MessageDialog dialog(message);
 		dialog.runModal();
@@ -344,8 +343,7 @@ void initGraphics(int width, int height, const Graphics::PixelFormat *format) {
 
 	if (gfxError & OSystem::kTransactionStretchModeSwitchFailed) {
 		Common::U32String message;
-		message = Common::U32String::format(
-			_("Could not switch to stretch mode '%s'."), ConfMan.get("stretch_mode").c_str());
+		message = Common::U32String::format(_("Could not switch to stretch mode '%s'."), ConfMan.get("stretch_mode").c_str());
 
 		GUI::MessageDialog dialog(message);
 		dialog.runModal();
@@ -402,6 +400,14 @@ void GUIErrorMessageWithURL(const Common::U32String &msg, const char *url) {
 	GUIErrorMessage(msg, url);
 }
 
+void GUIErrorMessageWithURL(const Common::String &msg, const char *url) {
+	GUIErrorMessage(Common::U32String(msg), url);
+}
+
+void GUIErrorMessage(const Common::String &msg, const char *url) {
+	GUIErrorMessage(Common::U32String(msg), url);
+}
+
 void GUIErrorMessage(const Common::U32String &msg, const char *url) {
 	g_system->setWindowCaption("Error");
 	g_system->beginGFXTransaction();
diff --git a/engines/engine.h b/engines/engine.h
index 46f939e9b90..a5dde6b0b0a 100644
--- a/engines/engine.h
+++ b/engines/engine.h
@@ -54,7 +54,9 @@ class Dialog;
  * Initializes graphics and shows error message.
  */
 void GUIErrorMessage(const Common::U32String &msg, const char *url = nullptr);
+void GUIErrorMessage(const Common::String &msg, const char *url = nullptr); // Redirect to GUIErrorMessage with U32Strings
 void GUIErrorMessageWithURL(const Common::U32String &msg, const char *url);
+void GUIErrorMessageWithURL(const Common::String &msg, const char *url); // Redirect to GUIErrorMessageWithURL with U32Strings
 void GUIErrorMessageFormat(Common::U32String fmt, ...);
 void GUIErrorMessageFormat(const char *fmt, ...) GCC_PRINTF(1, 2);
 
diff --git a/engines/game.cpp b/engines/game.cpp
index 7b9a67c1aa5..6f2c7c25b85 100644
--- a/engines/game.cpp
+++ b/engines/game.cpp
@@ -169,9 +169,9 @@ Common::String generateUnknownGameReport(const DetectedGames &detectedGames, boo
 	assert(!detectedGames.empty());
 
 	const char *reportStart = _s("The game in '%s' seems to be an unknown game variant.\n\n"
-									"Please report the following data to the ScummVM team at %s "
-									"along with the name of the game you tried to add and "
-									"its version, language, etc.:");
+								"Please report the following data to the ScummVM team at %s "
+								"along with the name of the game you tried to add and "
+								"its version, language, etc.:");
 	const char *reportEngineHeader = _s("Matched game IDs for the %s engine:");
 
 	Common::String report = Common::String::format(
diff --git a/engines/glk/alan2/alan2.cpp b/engines/glk/alan2/alan2.cpp
index 8008fd4c4b5..d875deecb3a 100644
--- a/engines/glk/alan2/alan2.cpp
+++ b/engines/glk/alan2/alan2.cpp
@@ -85,7 +85,7 @@ bool Alan2::initialize() {
 	// Open up the text file
 	txtfil = new Common::File();
 	if (!txtfil->open(Common::String::format("%s.dat", _advName.c_str()))) {
-		GUIErrorMessage(Common::convertToU32String("Could not open adventure text data file"));
+		GUIErrorMessage("Could not open adventure text data file");
 		delete txtfil;
 		return false;
 	}
diff --git a/engines/glk/alan3/alan3.cpp b/engines/glk/alan3/alan3.cpp
index 90baedd9f6b..d2bce655dc3 100644
--- a/engines/glk/alan3/alan3.cpp
+++ b/engines/glk/alan3/alan3.cpp
@@ -94,7 +94,7 @@ bool Alan3::initialize() {
 	// In Alan 3, the text data comes from the adventure file itself
 	Common::File *txt = new Common::File();
 	if (!txt->open(getFilename())) {
-	    GUIErrorMessage(Common::convertToU32String("Could not open adventure file for text data"));
+	    GUIErrorMessage("Could not open adventure file for text data");
 	    delete txt;
 	    return false;
 	}
diff --git a/engines/glk/hugo/herun.cpp b/engines/glk/hugo/herun.cpp
index 0e46a4789a3..1d8a79acb4e 100644
--- a/engines/glk/hugo/herun.cpp
+++ b/engines/glk/hugo/herun.cpp
@@ -184,7 +184,7 @@ Start:
 	// Handle any savegame selected directly from the ScummVM launcher
 	if (_savegameSlot != -1) {
 		if (loadGameState(_savegameSlot).getCode() != Common::kNoError) {
-			GUIErrorMessage(Common::convertToU32String("Loading failed"));
+			GUIErrorMessage("Loading failed");
 			_savegameSlot = -1;
 		}
 	}
diff --git a/engines/glk/hugo/hugo.cpp b/engines/glk/hugo/hugo.cpp
index dea8537c464..3e70d722afd 100644
--- a/engines/glk/hugo/hugo.cpp
+++ b/engines/glk/hugo/hugo.cpp
@@ -23,6 +23,7 @@
 #include "glk/hugo/hugo.h"
 #include "glk/hugo/resource_archive.h"
 #include "common/config-manager.h"
+#include "common/translation.h"
 
 namespace Glk {
 namespace Hugo {
@@ -179,14 +180,14 @@ Common::Error Hugo::readSaveData(Common::SeekableReadStream *rs) {
 	if (hugo_ferror(rs)) goto RestoreError;
 
 	if (strcmp(testid, id)) {
-		GUIErrorMessage(Common::convertToU32String("Incorrect rs file."));
+		GUIErrorMessage(_("Incorrect rs file."));
 		goto RestoreError;
 	}
 
 	/* Check serial number */
 	if (!hugo_fgets(testserial, 9, rs)) goto RestoreError;
 	if (strcmp(testserial, serial)) {
-		GUIErrorMessage(Common::convertToU32String("Save file created by different version."));
+		GUIErrorMessage(_("Save file created by different version."));
 		goto RestoreError;
 	}
 
diff --git a/engines/glk/zcode/zcode.cpp b/engines/glk/zcode/zcode.cpp
index 818aec711f6..5ff22ed723f 100644
--- a/engines/glk/zcode/zcode.cpp
+++ b/engines/glk/zcode/zcode.cpp
@@ -123,7 +123,7 @@ Common::Error ZCode::loadGameState(int slot) {
 			|| h_screen_cols != old_screen_cols))
 			erase_window(1);
 	} else {
-		error("%s", _("Error reading save file").encode().c_str());
+		error("%s", ("Error reading save file"));
 	}
 
 	return Common::kNoError;
diff --git a/engines/hdb/detection.cpp b/engines/hdb/detection.cpp
index f04227ead2b..438ec89e03e 100644
--- a/engines/hdb/detection.cpp
+++ b/engines/hdb/detection.cpp
@@ -254,7 +254,7 @@ SaveStateList HDBMetaEngine::listSaves(const char *target) const {
 				if (slotNum < 8)
 					desc.setDescription(Common::String::format("Auto: %s", mapName));
 				else
-					desc.setDescription(Common::convertToU32String(mapName));
+					desc.setDescription(mapName);
 
 				saveList.push_back(desc);
 			}
@@ -284,7 +284,7 @@ SaveStateDescriptor HDBMetaEngine::querySaveMetaInfos(const char *target, int sl
 
 		desc.setSaveSlot(slot);
 		desc.setPlayTime(timeSeconds * 1000);
-		desc.setDescription(Common::convertToU32String(mapName));
+		desc.setDescription(mapName);
 
 		return desc;
 	}
diff --git a/engines/hugo/hugo.cpp b/engines/hugo/hugo.cpp
index 82350ab1d56..3c053d96277 100644
--- a/engines/hugo/hugo.cpp
+++ b/engines/hugo/hugo.cpp
@@ -435,7 +435,7 @@ bool HugoEngine::loadHugoDat() {
 	if (!in.isOpen()) {
 		Common::U32String errorMessage = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
 		GUIErrorMessage(errorMessage);
-		warning("%s", errorMessage.encode().c_str());
+		warning("Unable to locate the '%s' engine data file.", filename.c_str());
 		return false;
 	}
 
@@ -453,9 +453,9 @@ bool HugoEngine::loadHugoDat() {
 	int minVer = in.readByte();
 
 	if ((majVer != HUGO_DAT_VER_MAJ) || (minVer != HUGO_DAT_VER_MIN)) {
-		Common::String errorMessage = Common::String::format(
-			_("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d.").encode().c_str(),
-			filename.c_str(),HUGO_DAT_VER_MAJ, HUGO_DAT_VER_MIN, majVer, minVer);
+		Common::U32String errorMessage = Common::U32String::format(
+			_("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d."),
+			filename.c_str(), HUGO_DAT_VER_MAJ, HUGO_DAT_VER_MIN, majVer, minVer);
 		GUIErrorMessage(errorMessage);
 		return false;
 	}
diff --git a/engines/illusions/menusystem.cpp b/engines/illusions/menusystem.cpp
index c00dace72dc..1ac2acdccc4 100644
--- a/engines/illusions/menusystem.cpp
+++ b/engines/illusions/menusystem.cpp
@@ -697,7 +697,7 @@ MenuActionSaveGame::MenuActionSaveGame(BaseMenuSystem *menuSystem, uint choiceIn
 
 void MenuActionSaveGame::execute() {
 	GUI::SaveLoadChooser *dialog;
-	Common::U32String desc;
+	Common::String desc;
 	int slot;
 
 	dialog = new GUI::SaveLoadChooser(_("Save game:"), _("Save"), true);
diff --git a/engines/lab/engine.cpp b/engines/lab/engine.cpp
index 0703edb64c3..f2913b229e4 100644
--- a/engines/lab/engine.cpp
+++ b/engines/lab/engine.cpp
@@ -122,7 +122,7 @@ void LabEngine::handleTrialWarning() {
 			// Wyrmkeep trial version
 			_extraGameFeatures = GF_WINDOWS_TRIAL;
 
-			GUI::MessageDialog trialMessage(Common::convertToU32String("This is a trial Windows version of the game. To play the full version, you will need to use the original interpreter and purchase a key from Wyrmkeep"));
+			GUI::MessageDialog trialMessage(_("This is a trial Windows version of the game. To play the full version, you will need to use the original interpreter and purchase a key from Wyrmkeep"));
 			trialMessage.runModal();
 		}
 		else {
diff --git a/engines/lab/processroom.cpp b/engines/lab/processroom.cpp
index 3860bd6448d..c7038021742 100644
--- a/engines/lab/processroom.cpp
+++ b/engines/lab/processroom.cpp
@@ -327,7 +327,7 @@ void LabEngine::doActions(const ActionList &actionList) {
 				// This is a Wyrmkeep Windows trial version, thus stop at this
 				// point, since we can't check for game payment status
 				_graphics->readPict(getPictName(true));
-				GUI::MessageDialog trialMessage(Common::convertToU32String("This is the end of the trial version. You can play the full game using the original interpreter from Wyrmkeep"));
+				GUI::MessageDialog trialMessage(_("This is the end of the trial version. You can play the full game using the original interpreter from Wyrmkeep"));
 				trialMessage.runModal();
 				break;
 			}
diff --git a/engines/lab/speciallocks.cpp b/engines/lab/speciallocks.cpp
index ef7f588bbdf..361e0698439 100644
--- a/engines/lab/speciallocks.cpp
+++ b/engines/lab/speciallocks.cpp
@@ -146,7 +146,7 @@ void SpecialLocks::changeTile(uint16 col, uint16 row) {
 
 	if (scrolltype != -1) {
 		if (_vm->getFeatures() & GF_WINDOWS_TRIAL) {
-			GUI::MessageDialog trialMessage(Common::convertToU32String("This puzzle is not available in the trial version of the game"));
+			GUI::MessageDialog trialMessage(_("This puzzle is not available in the trial version of the game"));
 			trialMessage.runModal();
 			return;
 		}
diff --git a/engines/lure/surface.cpp b/engines/lure/surface.cpp
index 8ce1be5bf62..ad5d0e4d96b 100644
--- a/engines/lure/surface.cpp
+++ b/engines/lure/surface.cpp
@@ -491,7 +491,7 @@ Surface *Surface::newDialog(uint16 width, uint8 numLines, const char **lines, bo
 		Common::TextToSpeechManager *ttsMan = g_system->getTextToSpeechManager();
 		if (ttsMan != nullptr) {
 			ttsMan->stop();
-			ttsMan->say(Common::convertToU32String(text.c_str()));
+			ttsMan->say(text.c_str());
 		}
 	}
 #endif
diff --git a/engines/mads/dialogs.cpp b/engines/mads/dialogs.cpp
index 5b99d906b2b..cadb7ae0f03 100644
--- a/engines/mads/dialogs.cpp
+++ b/engines/mads/dialogs.cpp
@@ -393,7 +393,7 @@ void TextDialog::draw() {
 		Common::TextToSpeechManager *ttsMan = g_system->getTextToSpeechManager();
 		if (ttsMan != nullptr) {
 			ttsMan->stop();
-			ttsMan->say(Common::convertToU32String(text.c_str()));
+			ttsMan->say(text.c_str());
 		}
 	}
 #endif
diff --git a/engines/mohawk/dialogs.cpp b/engines/mohawk/dialogs.cpp
index 7244a4f47fc..e18d276d794 100644
--- a/engines/mohawk/dialogs.cpp
+++ b/engines/mohawk/dialogs.cpp
@@ -142,7 +142,7 @@ MystOptionsWidget::MystOptionsWidget(GuiObject *boss, const Common::String &name
 
 			const MystLanguage *languages = MohawkEngine_Myst::listLanguages();
 			while (languages->language != Common::UNK_LANG) {
-				_languagePopUp->appendEntry(Common::convertToU32String(Common::getLanguageDescription(languages->language)), languages->language);
+				_languagePopUp->appendEntry(Common::getLanguageDescription(languages->language), languages->language);
 				languages++;
 			}
 		}
@@ -344,7 +344,7 @@ RivenOptionsWidget::RivenOptionsWidget(GuiObject *boss, const Common::String &na
 
 		const RivenLanguage *languages = MohawkEngine_Riven::listLanguages();
 		while (languages->language != Common::UNK_LANG) {
-			_languagePopUp->appendEntry(Common::convertToU32String(Common::getLanguageDescription(languages->language)), languages->language);
+			_languagePopUp->appendEntry(Common::getLanguageDescription(languages->language), languages->language);
 			languages++;
 		}
 	}
diff --git a/engines/mohawk/myst.cpp b/engines/mohawk/myst.cpp
index 28db0c4f824..1b426518d1e 100644
--- a/engines/mohawk/myst.cpp
+++ b/engines/mohawk/myst.cpp
@@ -560,7 +560,7 @@ Common::KeymapArray MohawkEngine_Myst::initKeymaps(const char *target) {
 	bool is25th = checkGameGUIOption(GAMEOPTION_25TH, guiOptions);
 	bool isDemo = checkGameGUIOption(GAMEOPTION_DEMO, guiOptions);
 
-	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "myst", Common::convertToU32String("Myst"));
+	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "myst", "Myst");
 
 	Action *act;
 
diff --git a/engines/mohawk/myst_stacks/preview.cpp b/engines/mohawk/myst_stacks/preview.cpp
index 5152674604f..a4f70c34842 100644
--- a/engines/mohawk/myst_stacks/preview.cpp
+++ b/engines/mohawk/myst_stacks/preview.cpp
@@ -29,6 +29,7 @@
 #include "mohawk/myst_stacks/preview.h"
 
 #include "common/system.h"
+#include "common/translation.h"
 #include "gui/message.h"
 
 namespace Mohawk {
@@ -86,7 +87,7 @@ void Preview::o_fadeFromBlack(uint16 var, const ArgumentsArray &args) {
 
 void Preview::o_stayHere(uint16 var, const ArgumentsArray &args) {
 	// Nuh-uh! No leaving the library in the demo!
-	GUI::MessageDialog dialog(Common::convertToU32String("You can't leave the library in the demo."));
+	GUI::MessageDialog dialog(_("You can't leave the library in the demo."));
 	dialog.runModal();
 }
 
diff --git a/engines/mohawk/riven.cpp b/engines/mohawk/riven.cpp
index 49eda7b88e0..149bacd8bd9 100644
--- a/engines/mohawk/riven.cpp
+++ b/engines/mohawk/riven.cpp
@@ -156,7 +156,8 @@ Common::Error MohawkEngine_Riven::run() {
 		Common::U32String message = _("You're missing a Riven executable. The Windows executable is 'riven.exe' or 'rivendmo.exe'. ");
 		message += _("Using the 'arcriven.z' installer file also works. In addition, you can use the Mac 'Riven' executable.");
 		GUIErrorMessage(message);
-		warning("%s", message.encode().c_str());
+		warning("You're missing a Riven executable. The Windows executable is 'riven.exe' or 'rivendmo.exe'. \
+			Using the 'arcriven.z' installer file also works. In addition, you can use the Mac 'Riven' executable.");
 		return Common::kNoGameDataFoundError;
 	}
 
@@ -167,7 +168,7 @@ Common::Error MohawkEngine_Riven::run() {
 	if (!_extrasFile->openFile("extras.mhk")) {
 		Common::U32String message = _("You're missing 'extras.mhk'. Using the 'arcriven.z' installer file also works.");
 		GUIErrorMessage(message);
-		warning("%s", message.encode().c_str());
+		warning("You're missing 'extras.mhk'. Using the 'arcriven.z' installer file also works.");
 		return Common::kNoGameDataFoundError;
 	}
 
@@ -498,8 +499,8 @@ bool MohawkEngine_Riven::checkDatafiles() {
 		return true;
 	}
 
-	Common::U32String message = _("You are missing the following required Riven data files:\n") + Common::convertToU32String(missingFiles.c_str());
-	warning("%s", message.encode().c_str());
+	Common::U32String message = _("You are missing the following required Riven data files:\n") + Common::U32String(missingFiles);
+	warning("You are missing the following required Riven data files:\n%s", missingFiles.c_str());
 	GUIErrorMessage(message);
 
 	return false;
@@ -829,7 +830,7 @@ Common::KeymapArray MohawkEngine_Riven::initKeymaps(const char *target) {
 	bool is25th = checkGameGUIOption(GAMEOPTION_25TH, guiOptions);
 	bool isDemo = checkGameGUIOption(GAMEOPTION_DEMO, guiOptions);
 
-	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "riven", Common::convertToU32String("Riven"));
+	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "riven", "Riven");
 
 	Action *act;
 
diff --git a/engines/mutationofjb/util.cpp b/engines/mutationofjb/util.cpp
index cab8eea6d7c..e4c855ce3e8 100644
--- a/engines/mutationofjb/util.cpp
+++ b/engines/mutationofjb/util.cpp
@@ -32,7 +32,7 @@ namespace MutationOfJB {
 void reportFileMissingError(const char *fileName) {
 	Common::U32String errorMessage = Common::U32String::format(_("Unable to locate the '%s' engine data file"), fileName);
 	GUIErrorMessage(errorMessage);
-	warning("%s", errorMessage.encode().c_str());
+	warning("Unable to locate the '%s' engine data file", fileName);
 }
 
 Common::String toUpperCP895(const Common::String &str) {
diff --git a/engines/pegasus/pegasus.cpp b/engines/pegasus/pegasus.cpp
index 5fa1e0652e6..4affc6f244a 100644
--- a/engines/pegasus/pegasus.cpp
+++ b/engines/pegasus/pegasus.cpp
@@ -2476,7 +2476,7 @@ uint PegasusEngine::getNeighborhoodCD(const NeighborhoodID neighborhood) const {
 Common::KeymapArray PegasusEngine::initKeymaps() {
 	using namespace Common;
 
-	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "pegasus", Common::convertToU32String("Pegasus Prime"));
+	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "pegasus", "Pegasus Prime");
 
 	Action *act;
 
diff --git a/engines/saga/saga.cpp b/engines/saga/saga.cpp
index f83c5a983c4..4f6ad22b44e 100644
--- a/engines/saga/saga.cpp
+++ b/engines/saga/saga.cpp
@@ -25,6 +25,7 @@
 #include "common/config-manager.h"
 #include "common/system.h"
 #include "common/events.h"
+#include "common/translation.h"
 
 #include "audio/mixer.h"
 
@@ -243,7 +244,7 @@ Common::Error SagaEngine::run() {
 
 	// Detect game and open resource files
 	if (!initGame()) {
-		GUIErrorMessage(Common::convertToU32String("Error loading game resources."));
+		GUIErrorMessage(_("Error loading game resources."));
 		return Common::kUnknownError;
 	}
 
diff --git a/engines/savestate.h b/engines/savestate.h
index ae8e0649a27..62ded23ba23 100644
--- a/engines/savestate.h
+++ b/engines/savestate.h
@@ -69,6 +69,7 @@ public:
 	 * @param desc A human readable description of the save state.
 	 */
 	void setDescription(const Common::U32String &desc) { _description = desc; }
+	void setDescription(const Common::String &desc) { _description = Common::U32String(desc); }
 
 	/**
 	 * @return A human readable description of the save state.
diff --git a/engines/sci/detection.cpp b/engines/sci/detection.cpp
index 7166933e124..b47191b7c05 100644
--- a/engines/sci/detection.cpp
+++ b/engines/sci/detection.cpp
@@ -1017,7 +1017,7 @@ SaveStateDescriptor SciMetaEngine::querySaveMetaInfos(const char *target, int sl
 			// invalid
 			delete in;
 
-			descriptor.setDescription(Common::convertToU32String("*Invalid*"));
+			descriptor.setDescription("*Invalid*");
 			return descriptor;
 		}
 
@@ -1028,7 +1028,7 @@ SaveStateDescriptor SciMetaEngine::querySaveMetaInfos(const char *target, int sl
 			// invalid
 			delete in;
 
-			descriptor.setDescription(Common::convertToU32String("*Invalid*"));
+			descriptor.setDescription("*Invalid*");
 			return descriptor;
 		}
 		descriptor.setThumbnail(thumbnail);
diff --git a/engines/sci/engine/kmisc.cpp b/engines/sci/engine/kmisc.cpp
index 8ea18be757b..815d9416fdc 100644
--- a/engines/sci/engine/kmisc.cpp
+++ b/engines/sci/engine/kmisc.cpp
@@ -23,6 +23,7 @@
 #include "common/config-manager.h"
 #include "common/savefile.h"
 #include "common/system.h"
+#include "common/translation.h"
 
 #include "sci/sci.h"
 #include "sci/debug.h"
@@ -870,7 +871,7 @@ reg_t kWinDLL(EngineState *s, int argc, reg_t *argv) {
 	switch (operation) {
 	case 0:	// load DLL
 		if (dllName == "PENGIN16.DLL")
-			showScummVMDialog(Common::convertToU32String("The Poker logic is hardcoded in an external DLL, and is not implemented yet. There exists some dummy logic for now, where opponent actions are chosen randomly"));
+			showScummVMDialog(_("The Poker logic is hardcoded in an external DLL, and is not implemented yet. There exists some dummy logic for now, where opponent actions are chosen randomly"));
 
 		// This is originally a call to LoadLibrary() and to the Watcom function GetIndirectFunctionHandle
 		return make_reg(0, 1000);	// fake ID for loaded DLL, normally returned from Windows LoadLibrary()
diff --git a/engines/sci/sound/music.cpp b/engines/sci/sound/music.cpp
index c2637b57ea7..49d9da316da 100644
--- a/engines/sci/sound/music.cpp
+++ b/engines/sci/sound/music.cpp
@@ -160,7 +160,7 @@ void SciMusic::init() {
 				Common::U32String message = _(
 					"The selected audio driver requires the following file(s):\n\n"
 				);
-				message += Common::convertToU32String(missingFiles);
+				message += Common::U32String(missingFiles);
 				message += _("\n\n"
 					"Some audio drivers (at least for some games) were made\n"
 					"available by Sierra as aftermarket patches and thus might not\n"
diff --git a/engines/scumm/dialogs.cpp b/engines/scumm/dialogs.cpp
index a0ac0aa8ad3..2d16afb2e62 100644
--- a/engines/scumm/dialogs.cpp
+++ b/engines/scumm/dialogs.cpp
@@ -609,7 +609,7 @@ void SubtitleSettingsDialog::cycleValue() {
 		_value = 0;
 
 	if (_value == 1 && g_system->getOverlayWidth() <= 320)
-		setInfoText(Common::convertToU32String(_sc("Speech & Subs", "lowres")));
+		setInfoText(Common::U32String(_sc("Speech & Subs", "lowres")));
 	else
 		setInfoText(_(subtitleDesc[_value]));
 
@@ -617,7 +617,7 @@ void SubtitleSettingsDialog::cycleValue() {
 }
 
 Indy3IQPointsDialog::Indy3IQPointsDialog(ScummEngine *scumm, char* text)
-	: InfoDialog(scumm, U32String(text)) {
+	: InfoDialog(scumm, Common::U32String(text)) {
 }
 
 void Indy3IQPointsDialog::handleKeyDown(Common::KeyState state) {
diff --git a/engines/scumm/resource.cpp b/engines/scumm/resource.cpp
index a894be6d4de..eebd36c78c8 100644
--- a/engines/scumm/resource.cpp
+++ b/engines/scumm/resource.cpp
@@ -232,7 +232,7 @@ void ScummEngine::askForDisk(const char *filename, int disknum) {
 #endif
 	} else {
 		sprintf(buf, "Cannot find file: '%s'", filename);
-		InfoDialog dialog(this, Common::convertToU32String(buf));
+		InfoDialog dialog(this, Common::U32String(buf));
 		runDialog(dialog);
 		error("Cannot find file: '%s'", filename);
 	}
diff --git a/engines/scumm/scumm.cpp b/engines/scumm/scumm.cpp
index a816dbc3fb2..aa2b041a256 100644
--- a/engines/scumm/scumm.cpp
+++ b/engines/scumm/scumm.cpp
@@ -2476,7 +2476,7 @@ void ScummEngine::scummLoop_handleSaveLoad() {
 			char buf[256];
 			snprintf(buf, sizeof(buf), _("Successfully saved game in file:\n\n%s").encode().c_str(), filename.c_str());
 
-			GUI::TimedMessageDialog dialog(Common::convertToU32String(buf), 1500);
+			GUI::TimedMessageDialog dialog(Common::U32String(buf), 1500);
 			runDialog(dialog);
 		}
 		if (success && _saveLoadFlag != 1)
diff --git a/engines/scumm/string.cpp b/engines/scumm/string.cpp
index 3ef6b9b766e..8a2ef97f4b3 100644
--- a/engines/scumm/string.cpp
+++ b/engines/scumm/string.cpp
@@ -115,7 +115,7 @@ void ScummEngine::showMessageDialog(const byte *msg) {
 	if (_string[3].color == 0)
 		_string[3].color = 4;
 
-	InfoDialog dialog(this, Common::convertToU32String((char *)buf));
+	InfoDialog dialog(this, Common::U32String((char *)buf));
 	VAR(VAR_KEYPRESS) = runDialog(dialog);
 }
 
diff --git a/engines/sherlock/scalpel/scalpel_user_interface.cpp b/engines/sherlock/scalpel/scalpel_user_interface.cpp
index 0a01dc01929..f819acf7f11 100644
--- a/engines/sherlock/scalpel/scalpel_user_interface.cpp
+++ b/engines/sherlock/scalpel/scalpel_user_interface.cpp
@@ -2069,7 +2069,7 @@ void ScalpelUserInterface::printObjectDesc(const Common::String &str, bool first
 		Common::TextToSpeechManager *ttsMan = g_system->getTextToSpeechManager();
 		if (ttsMan != nullptr) {
 			ttsMan->stop();
-			ttsMan->say(Common::convertToU32String(str.c_str()));
+			ttsMan->say(str.c_str());
 		}
 	}
 #endif
diff --git a/engines/sherlock/talk.cpp b/engines/sherlock/talk.cpp
index 7c823b97a18..f92b7c142a9 100644
--- a/engines/sherlock/talk.cpp
+++ b/engines/sherlock/talk.cpp
@@ -362,7 +362,7 @@ void Talk::talkTo(const Common::String filename) {
 				Common::TextToSpeechManager *ttsMan = g_system->getTextToSpeechManager();
 				if (ttsMan != nullptr) {
 					ttsMan->stop();
-					ttsMan->say(Common::convertToU32String(_statements[select]._reply.c_str()));
+					ttsMan->say(_statements[select]._reply.c_str());
 				}
 			}
 #endif
diff --git a/engines/sky/compact.cpp b/engines/sky/compact.cpp
index 802d03025c5..7a4b528cd22 100644
--- a/engines/sky/compact.cpp
+++ b/engines/sky/compact.cpp
@@ -130,7 +130,7 @@ SkyCompact::SkyCompact() {
 	if (!_cptFile->open(filename.c_str())) {
                 Common::U32String msg = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
                 GUIErrorMessage(msg);
-                error("%s", msg.encode().c_str());
+                error("Unable to locate the '%s' engine data file.", filename.c_str());
 	}
 
 	uint16 fileVersion = _cptFile->readUint16LE();
diff --git a/engines/sky/detection.cpp b/engines/sky/detection.cpp
index 0984ad0b74a..654ca2c4a88 100644
--- a/engines/sky/detection.cpp
+++ b/engines/sky/detection.cpp
@@ -209,7 +209,7 @@ Common::KeymapArray SkyMetaEngine::initKeymaps(const char *target) const {
 	using namespace Common;
 	using namespace Sky;
 
-	Keymap *mainKeymap = new Keymap(Keymap::kKeymapTypeGame, "sky-main", Common::convertToU32String("Beneath a Steel Sky"));
+	Keymap *mainKeymap = new Keymap(Keymap::kKeymapTypeGame, "sky-main", "Beneath a Steel Sky");
 
 	Action *act;
 
@@ -237,7 +237,7 @@ Common::KeymapArray SkyMetaEngine::initKeymaps(const char *target) const {
 	act->addDefaultInputMapping("JOY_Y");
 	mainKeymap->addAction(act);
 
-	Keymap *shortcutsKeymap = new Keymap(Keymap::kKeymapTypeGame, SkyEngine::shortcutsKeymapId, Common::convertToU32String("Beneath a Steel Sky - Shortcuts"));
+	Keymap *shortcutsKeymap = new Keymap(Keymap::kKeymapTypeGame, SkyEngine::shortcutsKeymapId, "Beneath a Steel Sky - Shortcuts");
 
 	act = new Action(kStandardActionOpenMainMenu, _("Open control panel"));
 	act->setCustomEngineActionEvent(kSkyActionOpenControlPanel);
diff --git a/engines/supernova/supernova.cpp b/engines/supernova/supernova.cpp
index 369a9526c2a..52e4a679114 100644
--- a/engines/supernova/supernova.cpp
+++ b/engines/supernova/supernova.cpp
@@ -824,8 +824,8 @@ bool SupernovaEngine::saveGame(int slot, const Common::String &description) {
 
 void SupernovaEngine::errorTempSave(bool saving) {
 	GUIErrorMessage(saving
-		? Common::convertToU32String("Failed to save temporary game state. Make sure your save game directory is set in ScummVM and that you can write to it.")
-		: Common::convertToU32String("Failed to load temporary game state."));
+		? _("Failed to save temporary game state. Make sure your save game directory is set in ScummVM and that you can write to it.")
+		: _("Failed to load temporary game state."));
 	error("Unrecoverable error");
 }
 
diff --git a/engines/sword2/protocol.cpp b/engines/sword2/protocol.cpp
index b1d57cb0798..caa1a21798f 100644
--- a/engines/sword2/protocol.cpp
+++ b/engines/sword2/protocol.cpp
@@ -305,7 +305,7 @@ byte *Sword2Engine::fetchPsxBackground(uint32 location) {
 	byte *buffer;
 
 	if (!file.open("screens.clu")) {
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot open screens.clu"));
+		GUIErrorMessage("Broken Sword II: Cannot open screens.clu");
 		return NULL;
 	}
 
@@ -373,7 +373,7 @@ byte *Sword2Engine::fetchPsxParallax(uint32 location, uint8 level) {
 		return NULL;
 
 	if (!file.open("screens.clu")) {
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot open screens.clu"));
+		GUIErrorMessage("Broken Sword II: Cannot open screens.clu");
 		return NULL;
 	}
 
diff --git a/engines/sword2/resman.cpp b/engines/sword2/resman.cpp
index dd89fe0fdd3..44027fd281c 100644
--- a/engines/sword2/resman.cpp
+++ b/engines/sword2/resman.cpp
@@ -104,7 +104,7 @@ bool ResourceManager::init() {
 	Common::File file;
 
 	if (!file.open("resource.inf")) {
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot open resource.inf"));
+		GUIErrorMessage("Broken Sword II: Cannot open resource.inf");
 		return false;
 	}
 
@@ -125,7 +125,7 @@ bool ResourceManager::init() {
 		_resFiles[_totalClusters].numEntries = -1;
 		_resFiles[_totalClusters].entryTab = NULL;
 		if (++_totalClusters >= MAX_res_files) {
-			GUIErrorMessage(Common::convertToU32String("Broken Sword II: Too many entries in resource.inf"));
+			GUIErrorMessage("Broken Sword II: Too many entries in resource.inf");
 			return false;
 		}
 	}
@@ -134,7 +134,7 @@ bool ResourceManager::init() {
 
 	// Now load in the binary id to res conversion table
 	if (!file.open("resource.tab")) {
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot open resource.tab"));
+		GUIErrorMessage("Broken Sword II: Cannot open resource.tab");
 		return false;
 	}
 
@@ -151,7 +151,7 @@ bool ResourceManager::init() {
 
 	if (file.eos() || file.err()) {
 		file.close();
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot read resource.tab"));
+		GUIErrorMessage("Broken Sword II: Cannot read resource.tab");
 		return false;
 	}
 
@@ -161,7 +161,7 @@ bool ResourceManager::init() {
 	// version, which has all files on one disc.
 
 	if (!file.open("cd.inf") && !Sword2Engine::isPsx()) {
-		GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot open cd.inf"));
+		GUIErrorMessage("Broken Sword II: Cannot open cd.inf");
 		return false;
 	}
 
@@ -179,7 +179,7 @@ bool ResourceManager::init() {
 			if (file.eos() || file.err()) {
 				delete[] cdInf;
 				file.close();
-				GUIErrorMessage(Common::convertToU32String("Broken Sword II: Cannot read cd.inf"));
+				GUIErrorMessage("Broken Sword II: Cannot read cd.inf");
 				return false;
 			}
 
diff --git a/engines/teenagent/resources.cpp b/engines/teenagent/resources.cpp
index cac15f5a868..5742c0d9db9 100644
--- a/engines/teenagent/resources.cpp
+++ b/engines/teenagent/resources.cpp
@@ -95,7 +95,7 @@ bool Resources::loadArchives(const ADGameDescription *gd) {
 	if (!dat_file->open(filename.c_str())) {
 		delete dat_file;
 		Common::U32String errorMessage = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
-		warning("%s", errorMessage.encode().c_str());
+		warning("Unable to locate the '%s' engine data file.", filename.c_str());
 		GUIErrorMessage(errorMessage);
 		return false;
 	}
diff --git a/engines/testbed/config.cpp b/engines/testbed/config.cpp
index c8313a6d6e1..5ecab08b7cc 100644
--- a/engines/testbed/config.cpp
+++ b/engines/testbed/config.cpp
@@ -34,8 +34,8 @@ TestbedOptionsDialog::TestbedOptionsDialog(Common::Array<Testsuite *> &tsList, T
 		GUI::Dialog("TestbedOptions"),
 		_testbedConfMan(tsConfMan) {
 
-	new GUI::StaticTextWidget(this, "TestbedOptions.Headline", Common::convertToU32String("Select Testsuites to Execute"));
-	new GUI::StaticTextWidget(this, "TestbedOptions.Info", Common::convertToU32String("Use Doubleclick to select/deselect"));
+	new GUI::StaticTextWidget(this, "TestbedOptions.Headline", Common::U32String("Select Testsuites to Execute"));
+	new GUI::StaticTextWidget(this, "TestbedOptions.Info", Common::U32String("Use Doubleclick to select/deselect"));
 
 	// Construct a String Array
 	Common::Array<Testsuite *>::const_iterator iter;
@@ -63,12 +63,12 @@ TestbedOptionsDialog::TestbedOptionsDialog(Common::Array<Testsuite *> &tsList, T
 	_testListDisplay->setEditable(false);
 
 	if (selected > (tsList.size() - selected)) {
-		_selectButton = new GUI::ButtonWidget(this, "TestbedOptions.SelectAll", Common::convertToU32String("Deselect All"), Common::U32String(""), kTestbedDeselectAll, 0);
+		_selectButton = new GUI::ButtonWidget(this, "TestbedOptions.SelectAll", Common::U32String("Deselect All"), Common::U32String(""), kTestbedDeselectAll, 0);
 	} else {
-		_selectButton = new GUI::ButtonWidget(this, "TestbedOptions.SelectAll", Common::convertToU32String("Select All"), Common::U32String(""), kTestbedSelectAll, 0);
+		_selectButton = new GUI::ButtonWidget(this, "TestbedOptions.SelectAll", Common::U32String("Select All"), Common::U32String(""), kTestbedSelectAll, 0);
 	}
-	new GUI::ButtonWidget(this, "TestbedOptions.RunTests", Common::convertToU32String("Run tests"), Common::U32String(""), GUI::kCloseCmd);
-	new GUI::ButtonWidget(this, "TestbedOptions.Quit", Common::convertToU32String("Exit Testbed"), Common::U32String(""), kTestbedQuitCmd);
+	new GUI::ButtonWidget(this, "TestbedOptions.RunTests", Common::U32String("Run tests"), Common::U32String(""), GUI::kCloseCmd);
+	new GUI::ButtonWidget(this, "TestbedOptions.Quit", Common::U32String("Exit Testbed"), Common::U32String(""), kTestbedQuitCmd);
 }
 
 TestbedOptionsDialog::~TestbedOptionsDialog() {}
@@ -102,7 +102,7 @@ void TestbedOptionsDialog::handleCommand(GUI::CommandSender *sender, uint32 cmd,
 		break;
 
 	case kTestbedDeselectAll:
-		_selectButton->setLabel(Common::convertToU32String("Select All"));
+		_selectButton->setLabel("Select All");
 		_selectButton->setCmd(kTestbedSelectAll);
 		for (uint i = 0; i < _testSuiteArray.size(); i++) {
 			_testListDisplay->markAsDeselected(i);
@@ -114,7 +114,7 @@ void TestbedOptionsDialog::handleCommand(GUI::CommandSender *sender, uint32 cmd,
 		break;
 
 	case kTestbedSelectAll:
-		_selectButton->setLabel(Common::convertToU32String("Deselect All"));
+		_selectButton->setLabel("Deselect All");
 		_selectButton->setCmd(kTestbedDeselectAll);
 		for (uint i = 0; i < _testSuiteArray.size(); i++) {
 			_testListDisplay->markAsSelected(i);
diff --git a/engines/testbed/config.h b/engines/testbed/config.h
index 02149e6d090..5a397a31448 100644
--- a/engines/testbed/config.h
+++ b/engines/testbed/config.h
@@ -73,7 +73,7 @@ public:
 
 	void markAsSelected(int i) {
 		if (!_list[i].encode().contains("selected")) {
-			_list[i] += Common::convertToU32String(" (selected)");
+			_list[i] += Common::U32String(" (selected)");
 		}
 		_listColors[i] = GUI::ThemeEngine::kFontColorNormal;
 		draw();
diff --git a/engines/testbed/speech.cpp b/engines/testbed/speech.cpp
index 034e3276300..754f7cc2634 100644
--- a/engines/testbed/speech.cpp
+++ b/engines/testbed/speech.cpp
@@ -59,7 +59,7 @@ TestExitStatus Speechtests::testMale() {
 		return kTestFailed;
 	}
 	ttsMan->setVoice(maleVoices[0]);
-	ttsMan->say(Common::convertToU32String("Testing text to speech with male voice."));
+	ttsMan->say("Testing text to speech with male voice.");
 	if (!ttsMan->isSpeaking()) {
 		Testsuite::logDetailedPrintf("Male TTS failed\n");
 		return kTestFailed;
@@ -96,7 +96,7 @@ TestExitStatus Speechtests::testFemale() {
 		return kTestFailed;
 	}
 	ttsMan->setVoice(femaleVoices[0]);
-	ttsMan->say(Common::convertToU32String("Testing text to speech with female voice."));
+	ttsMan->say("Testing text to speech with female voice.");
 	if (!ttsMan->isSpeaking()) {
 		Testsuite::logDetailedPrintf("Female TTS failed\n");
 		return kTestFailed;
@@ -128,7 +128,7 @@ TestExitStatus Speechtests::testStop() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("Testing text to speech, the speech should stop after approximately a second after it started, so it shouldn't have the time to read this."));
+	ttsMan->say("Testing text to speech, the speech should stop after approximately a second after it started, so it shouldn't have the time to read this.");
 	g_system->delayMillis(1000);
 	ttsMan->stop();
 	// It is allright if the voice isn't available right away, but a second should be
@@ -164,11 +164,11 @@ TestExitStatus Speechtests::testStopAndSpeak() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("Testing text to speech, the speech should stop after approximately a second after it started, so it shouldn't have the time to read this."));
+	ttsMan->say("Testing text to speech, the speech should stop after approximately a second after it started, so it shouldn't have the time to read this.");
 	g_system->delayMillis(1000);
 	ttsMan->stop();
-	ttsMan->say(Common::convertToU32String("Now starting the second sentence."), Common::TextToSpeechManager::QUEUE);
-	ttsMan->say(Common::convertToU32String("You should hear that one in totality."), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("Now starting the second sentence.", Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("You should hear that one in totality.", Common::TextToSpeechManager::QUEUE);
 	if (!ttsMan->isSpeaking()) {
 		Testsuite::logDetailedPrintf("Male TTS failed\n");
 		return kTestFailed;
@@ -201,14 +201,14 @@ TestExitStatus Speechtests::testPauseResume() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("Testing text to speech, the speech should pause after a second"));
+	ttsMan->say("Testing text to speech, the speech should pause after a second");
 	g_system->delayMillis(1000);
 	ttsMan->pause();
 	if (!ttsMan->isPaused()) {
 		Testsuite::logDetailedPrintf("TTS pause failed\n");
 		return kTestFailed;
 	}
-	ttsMan->say(Common::convertToU32String("and then resume again"), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("and then resume again", Common::TextToSpeechManager::QUEUE);
 	g_system->delayMillis(3000);
 	if (!ttsMan->isPaused()) {
 		Testsuite::logDetailedPrintf("TTS pause failed\n");
@@ -247,10 +247,10 @@ TestExitStatus Speechtests::testRate() {
 	}
 
 	ttsMan->setRate(-100);
-	ttsMan->say(Common::convertToU32String("Text to speech slow rate."));
+	ttsMan->say("Text to speech slow rate.");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->setRate(100);
-	ttsMan->say(Common::convertToU32String("Text to speech fast rate."));
+	ttsMan->say("Text to speech fast rate.");
 	waitForSpeechEnd(ttsMan);
 
 	Common::String prompt = "Did you hear a voice saying: \"Text to speech slow rate.\" slowly and then \"Text to speech fast rate.\" fast?";
@@ -280,10 +280,10 @@ TestExitStatus Speechtests::testVolume() {
 	}
 
 	ttsMan->setVolume(20);
-	ttsMan->say(Common::convertToU32String("Text to speech low volume."));
+	ttsMan->say("Text to speech low volume.");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->setVolume(100);
-	ttsMan->say(Common::convertToU32String("Text to speech max volume."));
+	ttsMan->say("Text to speech max volume.");
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice saying: \"Text to speech low volume.\" quietly and then \"Text to speech max volume.\" at a higher volume?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -312,10 +312,10 @@ TestExitStatus Speechtests::testPitch() {
 	}
 
 	ttsMan->setPitch(100);
-	ttsMan->say(Common::convertToU32String("Text to speech high pitch."));
+	ttsMan->say("Text to speech high pitch.");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->setPitch(-100);
-	ttsMan->say(Common::convertToU32String("Text to speech low pitch."));
+	ttsMan->say("Text to speech low pitch.");
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a high pitched voice saying: \"Text to speech high pitch.\" and then a low pitched voice: \"Text to speech low pitch.\" ?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -343,7 +343,7 @@ TestExitStatus Speechtests::testStateStacking() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("Voice number 1 is speaking"));
+	ttsMan->say("Voice number 1 is speaking");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->pushState();
 	Common::Array<int> femaleVoices = ttsMan->getVoiceIndicesByGender(Common::TTSVoice::FEMALE);
@@ -355,20 +355,20 @@ TestExitStatus Speechtests::testStateStacking() {
 	ttsMan->setVolume(80);
 	ttsMan->setPitch(40);
 	ttsMan->setRate(-30);
-	ttsMan->say(Common::convertToU32String("Voice number 2 is speaking"));
+	ttsMan->say("Voice number 2 is speaking");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->pushState();
 	ttsMan->setVoice(2 % allVoices.size());
 	ttsMan->setVolume(90);
 	ttsMan->setPitch(-80);
 	ttsMan->setRate(-50);
-	ttsMan->say(Common::convertToU32String("Voice number 3 is speaking"));
+	ttsMan->say("Voice number 3 is speaking");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->popState();
-	ttsMan->say(Common::convertToU32String("Voice number 2 is speaking"));
+	ttsMan->say("Voice number 2 is speaking");
 	waitForSpeechEnd(ttsMan);
 	ttsMan->popState();
-	ttsMan->say(Common::convertToU32String("Voice number 1 is speaking"));
+	ttsMan->say("Voice number 1 is speaking");
 	waitForSpeechEnd(ttsMan);
 
 	Common::String prompt = "Did you hear three different voices speaking in this order: 1, 2, 3, 2, 1 and each time the same voice spoke, it sounded the same?";
@@ -397,8 +397,8 @@ TestExitStatus Speechtests::testQueueing() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("This is first speech."));
-	ttsMan->say(Common::convertToU32String("This is second speech."), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("This is first speech.");
+	ttsMan->say("This is second speech.", Common::TextToSpeechManager::QUEUE);
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice saying: \"This is first speech. This is second speech\" ?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -426,9 +426,9 @@ TestExitStatus Speechtests::testInterrupting() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z"));
+	ttsMan->say("A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z");
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("Speech interrupted"), Common::TextToSpeechManager::INTERRUPT);
+	ttsMan->say("Speech interrupted", Common::TextToSpeechManager::INTERRUPT);
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice saying the engilsh alphabet, but it got interrupted and said: \"Speech interrupted\" instead?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -456,8 +456,8 @@ TestExitStatus Speechtests::testDroping() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("Today is a really nice weather, perfect day to use ScummVM, don't you think?"));
-	ttsMan->say(Common::convertToU32String("Speech interrupted, fail"), Common::TextToSpeechManager::DROP);
+	ttsMan->say("Today is a really nice weather, perfect day to use ScummVM, don't you think?");
+	ttsMan->say("Speech interrupted, fail", Common::TextToSpeechManager::DROP);
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice say: \"Today is a really nice weather, perfect day to use ScummVM, don't you think?\" and nothing else?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -485,16 +485,16 @@ TestExitStatus Speechtests::testInterruptNoRepeat() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("This is the first sentence, this should get interrupted"));
-	ttsMan->say(Common::convertToU32String("Failure"), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("This is the first sentence, this should get interrupted");
+	ttsMan->say("Failure", Common::TextToSpeechManager::QUEUE);
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("This is the second sentence, it should play only once"), Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
-	ttsMan->say(Common::convertToU32String("Failure"), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("This is the second sentence, it should play only once", Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
+	ttsMan->say("Failure", Common::TextToSpeechManager::QUEUE);
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("This is the second sentence, it should play only once"), Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
-	ttsMan->say(Common::convertToU32String("Failure"), Common::TextToSpeechManager::QUEUE);
+	ttsMan->say("This is the second sentence, it should play only once", Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
+	ttsMan->say("Failure", Common::TextToSpeechManager::QUEUE);
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("This is the second sentence, it should play only once"), Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
+	ttsMan->say("This is the second sentence, it should play only once", Common::TextToSpeechManager::INTERRUPT_NO_REPEAT);
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice say: \"This is the first sentence, this should get interrupted\", but it got interrupted and \"This is the second sentence, it should play only once.\" got said instead?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
@@ -522,14 +522,14 @@ TestExitStatus Speechtests::testQueueNoRepeat() {
 		return kTestSkipped;
 	}
 
-	ttsMan->say(Common::convertToU32String("This is the first sentence."));
-	ttsMan->say(Common::convertToU32String("This is the first sentence."), Common::TextToSpeechManager::QUEUE_NO_REPEAT);
+	ttsMan->say("This is the first sentence.");
+	ttsMan->say("This is the first sentence.", Common::TextToSpeechManager::QUEUE_NO_REPEAT);
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("This is the first sentence."), Common::TextToSpeechManager::QUEUE_NO_REPEAT);
-	ttsMan->say(Common::convertToU32String("This is the second sentence."), Common::TextToSpeechManager::QUEUE_NO_REPEAT);
-	ttsMan->say(Common::convertToU32String("This is the second sentence."), Common::TextToSpeechManager::QUEUE_NO_REPEAT);
+	ttsMan->say("This is the first sentence.", Common::TextToSpeechManager::QUEUE_NO_REPEAT);
+	ttsMan->say("This is the second sentence.", Common::TextToSpeechManager::QUEUE_NO_REPEAT);
+	ttsMan->say("This is the second sentence.", Common::TextToSpeechManager::QUEUE_NO_REPEAT);
 	g_system->delayMillis(1000);
-	ttsMan->say(Common::convertToU32String("This is the second sentence."), Common::TextToSpeechManager::QUEUE_NO_REPEAT);
+	ttsMan->say("This is the second sentence.", Common::TextToSpeechManager::QUEUE_NO_REPEAT);
 	waitForSpeechEnd(ttsMan);
 	Common::String prompt = "Did you hear a voice say: \"This is the first sentence. This the second sentence\" and nothing else?";
 	if (!Testsuite::handleInteractiveInput(prompt, "Yes", "No", kOptionLeft)) {
diff --git a/engines/testbed/testbed.cpp b/engines/testbed/testbed.cpp
index cf98513d04b..a68909b264e 100644
--- a/engines/testbed/testbed.cpp
+++ b/engines/testbed/testbed.cpp
@@ -67,7 +67,7 @@ void TestbedExitDialog::init() {
 		if ((*i)->isEnabled()) {
 			strArray.push_back(Common::String::format("Passed: %d  Failed: %d Skipped: %d", (*i)->getNumTestsPassed(), (*i)->getNumTestsFailed(), (*i)->getNumTestsSkipped()));
 		} else {
-			strArray.push_back(Common::convertToU32String("Skipped"));
+			strArray.push_back(Common::U32String("Skipped"));
 		}
 		colors.push_back(GUI::ThemeEngine::kFontColorAlternate);
 	}
diff --git a/engines/tinsel/sound.cpp b/engines/tinsel/sound.cpp
index 6794908772a..bf4a7e781c1 100644
--- a/engines/tinsel/sound.cpp
+++ b/engines/tinsel/sound.cpp
@@ -483,12 +483,12 @@ void SoundManager::setSFXVolumes(uint8 volume) {
 }
 
 void SoundManager::showSoundError(const char *errorMsg, const char *soundFile) {
-	Common::U32String msg;
+	Common::String msg;
 	msg = Common::String::format(errorMsg, soundFile);
-	GUI::MessageDialog dialog(msg);
+	GUI::MessageDialog dialog(msg.c_str(), "OK");
 	dialog.runModal();
 
-	error("%s", msg.encode().c_str());
+	error("%s", msg.c_str());
 }
 
 /**
diff --git a/engines/titanic/support/files_manager.cpp b/engines/titanic/support/files_manager.cpp
index 6835f2e6914..63fde3aaba5 100644
--- a/engines/titanic/support/files_manager.cpp
+++ b/engines/titanic/support/files_manager.cpp
@@ -39,19 +39,19 @@ CFilesManager::~CFilesManager() {
 
 bool CFilesManager::loadResourceIndex() {
 	if (!_datFile.open("titanic.dat")) {
-		GUIErrorMessage(Common::convertToU32String("Could not find titanic.dat data file"));
+		GUIErrorMessage("Could not find titanic.dat data file");
 		return false;
 	}
 
 	uint headerId = _datFile.readUint32BE();
 	_version = _datFile.readUint16LE();
 	if (headerId != MKTAG('S', 'V', 'T', 'N')) {
-		GUIErrorMessage(Common::convertToU32String("titanic.dat has invalid contents"));
+		GUIErrorMessage("titanic.dat has invalid contents");
 		return false;
 	}
 
 	if (_version != 5) {
-		GUIErrorMessage(Common::convertToU32String("titanic.dat is out of date"));
+		GUIErrorMessage("titanic.dat is out of date");
 		return false;
 	}
 
diff --git a/engines/tony/tony.cpp b/engines/tony/tony.cpp
index 99fd5d359ea..93cacd4b4b8 100644
--- a/engines/tony/tony.cpp
+++ b/engines/tony/tony.cpp
@@ -195,7 +195,7 @@ bool TonyEngine::loadTonyDat() {
 	if (!in.isOpen()) {
 		msg = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Unable to locate the '%s' engine data file.", filename.c_str());
 		return false;
 	}
 
@@ -207,7 +207,7 @@ bool TonyEngine::loadTonyDat() {
 	if (strcmp(buf, "TONY")) {
 		msg = Common::U32String::format(_("The '%s' engine data file is corrupt."), filename.c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("The '%s' engine data file is corrupt.", filename.c_str());
 		return false;
 	}
 
@@ -219,7 +219,8 @@ bool TonyEngine::loadTonyDat() {
 			_("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d."),
 			filename.c_str(), TONY_DAT_VER_MAJ, TONY_DAT_VER_MIN, majVer, minVer);
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d.",
+			filename.c_str(), TONY_DAT_VER_MAJ, TONY_DAT_VER_MIN, majVer, minVer);
 
 		return false;
 	}
@@ -255,7 +256,7 @@ bool TonyEngine::loadTonyDat() {
 	if (expectedLangVariant > numVariant - 1) {
 		msg = Common::U32String::format(_("Font variant not present in '%s' engine data file."), filename.c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Font variant not present in '%s' engine data file.", filename.c_str());
 
 		return false;
 	}
diff --git a/engines/toon/toon.cpp b/engines/toon/toon.cpp
index de02f4a6e52..712cd4344c6 100644
--- a/engines/toon/toon.cpp
+++ b/engines/toon/toon.cpp
@@ -245,7 +245,7 @@ void ToonEngine::parseInput() {
 					} else {
 						Common::U32String buf = Common::U32String::format(_("Could not quick load the saved game #%d"), slotNum);
 						GUI::MessageDialog dialog(buf);
-						warning("%s", buf.encode().c_str());
+						warning("Could not quick load the saved game #%d", slotNum);
 						dialog.runModal();
 					}
 				}
@@ -1526,7 +1526,7 @@ void ToonEngine::loadScene(int32 SceneId, bool forGameLoad) {
 	if (!resources()->openPackage(createRoomFilename(locationName + ".PAK"))) {
 		Common::U32String msg = Common::U32String::format(_("Unable to locate the '%s' data file."), createRoomFilename(locationName + ".PAK").c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Unable to locate the '%s' data file.", createRoomFilename(locationName + ".PAK").c_str());
 		_shouldQuit = true;
 		return;
 	}
@@ -4951,7 +4951,7 @@ bool ToonEngine::loadToonDat() {
 	if (!in.isOpen()) {
 		msg = Common::U32String::format(_("Unable to locate the '%s' engine data file."), filename.c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Unable to locate the '%s' engine data file.", filename.c_str());
 		return false;
 	}
 
@@ -4963,7 +4963,7 @@ bool ToonEngine::loadToonDat() {
 	if (strcmp(buf, "TOON")) {
 		msg = Common::U32String::format(_("The '%s' engine data file is corrupt."), filename.c_str());
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("The '%s' engine data file is corrupt.", filename.c_str());
 		return false;
 	}
 
@@ -4975,7 +4975,8 @@ bool ToonEngine::loadToonDat() {
 			_("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d."),
 			filename.c_str(), TOON_DAT_VER_MAJ, TOON_DAT_VER_MIN, majVer, minVer);
 		GUIErrorMessage(msg);
-		warning("%s", msg.encode().c_str());
+		warning("Incorrect version of the '%s' engine data file found. Expected %d.%d but got %d.%d.",
+			filename.c_str(), TOON_DAT_VER_MAJ, TOON_DAT_VER_MIN, majVer, minVer);
 
 		return false;
 	}
diff --git a/engines/tsage/core.cpp b/engines/tsage/core.cpp
index 5eac13fd06c..50bc6e7e908 100644
--- a/engines/tsage/core.cpp
+++ b/engines/tsage/core.cpp
@@ -1622,7 +1622,7 @@ void SceneItem::doAction(int action) {
 			break;
 		}
 
-		GUIErrorMessage(Common::convertToU32String(msg));
+		GUIErrorMessage(msg);
 	}
 }
 
@@ -4436,7 +4436,7 @@ void SceneHandler::dispatch() {
 		// FIXME: Make use of the description string in err to enhance
 		// the error reported to the user.
 		if (err.getCode() != Common::kNoError)
-			GUIErrorMessage(Common::convertToU32String(SAVE_ERROR_MSG));
+			GUIErrorMessage(SAVE_ERROR_MSG);
 	}
 	if (_loadGameSlot != -1) {
 		int priorSceneBeforeLoad = GLOBALS._sceneManager._previousScene;
diff --git a/engines/ultima/ultima4/meta_engine.cpp b/engines/ultima/ultima4/meta_engine.cpp
index 550750924bd..46384354e64 100644
--- a/engines/ultima/ultima4/meta_engine.cpp
+++ b/engines/ultima/ultima4/meta_engine.cpp
@@ -201,7 +201,7 @@ Common::KeymapArray MetaEngine::initKeymaps(KeybindingMode mode) {
 	for (int kCtr = 0; recPtr->_id; ++recPtr, ++kCtr) {
 		// Core keymaps
 		keyMap = new Common::Keymap(Common::Keymap::kKeymapTypeGame,
-			recPtr->_id, Common::convertToU32String(recPtr->_desc));
+			recPtr->_id, recPtr->_desc);
 		keymapArray.push_back(keyMap);
 
 		if (kCtr == 0) {
diff --git a/engines/wintermute/base/base_persistence_manager.cpp b/engines/wintermute/base/base_persistence_manager.cpp
index d0c495bf9c1..ad38f5d529f 100644
--- a/engines/wintermute/base/base_persistence_manager.cpp
+++ b/engines/wintermute/base/base_persistence_manager.cpp
@@ -153,7 +153,7 @@ void BasePersistenceManager::getSaveStateDesc(int slot, SaveStateDescriptor &des
 		return;
 	}
 	desc.setSaveSlot(slot);
-	desc.setDescription(Common::convertToU32String(_savedDescription));
+	desc.setDescription(_savedDescription);
 	desc.setDeletableFlag(true);
 	desc.setWriteProtectedFlag(false);
 
diff --git a/engines/wintermute/detection.cpp b/engines/wintermute/detection.cpp
index 0ead7579d4d..ebd54879739 100644
--- a/engines/wintermute/detection.cpp
+++ b/engines/wintermute/detection.cpp
@@ -209,7 +209,7 @@ public:
 	SaveStateDescriptor querySaveMetaInfos(const char *target, int slot) const override {
 		Wintermute::BasePersistenceManager pm(target, true);
 		SaveStateDescriptor retVal;
-		retVal.setDescription(Common::convertToU32String("Invalid savegame"));
+		retVal.setDescription("Invalid savegame");
 		pm.getSaveStateDesc(slot, retVal);
 		return retVal;
 	}
diff --git a/engines/wintermute/keymapper_tables.h b/engines/wintermute/keymapper_tables.h
index 52bc3b9557c..f65030661f7 100644
--- a/engines/wintermute/keymapper_tables.h
+++ b/engines/wintermute/keymapper_tables.h
@@ -34,9 +34,9 @@ inline Common::KeymapArray getWintermuteKeymaps(const char *target, const Common
 
 	using namespace Common;
 
-	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "wintermute", Common::convertToU32String("Wintermute engine"));
-	Keymap *gameKeyMap = new Keymap(Keymap::kKeymapTypeGame, gameId, Common::convertToU32String(gameDescr));
-	Keymap *extraKeyMap = new Keymap(Keymap::kKeymapTypeGame, "extras", Common::convertToU32String("ScummVM extra actions"));
+	Keymap *engineKeyMap = new Keymap(Keymap::kKeymapTypeGame, "wintermute", "Wintermute engine");
+	Keymap *gameKeyMap = new Keymap(Keymap::kKeymapTypeGame, gameId, gameDescr);
+	Keymap *extraKeyMap = new Keymap(Keymap::kKeymapTypeGame, "extras", "ScummVM extra actions");
 
 	Action *act;
 
diff --git a/engines/xeen/files.cpp b/engines/xeen/files.cpp
index 1a5ed968c5d..080246f3dda 100644
--- a/engines/xeen/files.cpp
+++ b/engines/xeen/files.cpp
@@ -255,14 +255,14 @@ bool FileManager::setup() {
 	// Ensure the custom CC archive is present
 	File f;
 	if (!f.exists("xeen.ccs")) {
-		GUIErrorMessage(Common::convertToU32String("Could not find xeen.ccs data file"));
+		GUIErrorMessage("Could not find xeen.ccs data file");
 		return false;
 	}
 
 	// Verify the version of the CC is correct
 	CCArchive *dataCc = new CCArchive("xeen.ccs", "data", true);
 	if (!f.open("VERSION", *dataCc) || f.readUint32LE() != 3) {
-		GUIErrorMessage(Common::convertToU32String("xeen.ccs is out of date"));
+		GUIErrorMessage("xeen.ccs is out of date");
 		return false;
 	}
 	SearchMan.add("data", dataCc);
diff --git a/engines/zvision/detection.cpp b/engines/zvision/detection.cpp
index 3723a8f217a..d97cee5ef4d 100644
--- a/engines/zvision/detection.cpp
+++ b/engines/zvision/detection.cpp
@@ -129,7 +129,7 @@ Common::KeymapArray ZVisionMetaEngine::initKeymaps(const char *target) const {
 	using namespace Common;
 	using namespace ZVision;
 
-	Keymap *mainKeymap = new Keymap(Keymap::kKeymapTypeGame, mainKeymapId, Common::convertToU32String("Z-Vision"));
+	Keymap *mainKeymap = new Keymap(Keymap::kKeymapTypeGame, mainKeymapId, "Z-Vision");
 
 	Action *act;
 
@@ -145,7 +145,7 @@ Common::KeymapArray ZVisionMetaEngine::initKeymaps(const char *target) const {
 	act->addDefaultInputMapping("JOY_B");
 	mainKeymap->addAction(act);
 
-	Keymap *gameKeymap = new Keymap(Keymap::kKeymapTypeGame, gameKeymapId, Common::convertToU32String("Z-Vision - Game"));
+	Keymap *gameKeymap = new Keymap(Keymap::kKeymapTypeGame, gameKeymapId, "Z-Vision - Game");
 
 	act = new Action(kStandardActionMoveUp, _("Look Up"));
 	act->setCustomEngineActionEvent(kZVisionActionUp);
@@ -232,7 +232,7 @@ Common::KeymapArray ZVisionMetaEngine::initKeymaps(const char *target) const {
 	act->addDefaultInputMapping("C+p");
 	gameKeymap->addAction(act);
 
-	Keymap *cutscenesKeymap = new Keymap(Keymap::kKeymapTypeGame, cutscenesKeymapId, Common::convertToU32String("Z-Vision - Cutscenes"));
+	Keymap *cutscenesKeymap = new Keymap(Keymap::kKeymapTypeGame, cutscenesKeymapId, "Z-Vision - Cutscenes");
 
 	act = new Action(kStandardActionSkip, _("Skip cutscene"));
 	act->setCustomEngineActionEvent(kZVisionActionSkipCutscene);
diff --git a/engines/zvision/zvision.cpp b/engines/zvision/zvision.cpp
index f630325b606..248610b9231 100644
--- a/engines/zvision/zvision.cpp
+++ b/engines/zvision/zvision.cpp
@@ -44,6 +44,7 @@
 #include "common/debug-channels.h"
 #include "common/textconsole.h"
 #include "common/timer.h"
+#include "common/translation.h"
 #include "common/error.h"
 #include "common/system.h"
 #include "common/file.h"
@@ -308,7 +309,7 @@ Common::Error ZVision::run() {
 	}
 
 	if (!foundAllFonts) {
-		GUI::MessageDialog dialog(Common::convertToU32String(
+		GUI::MessageDialog dialog(_(
 				"Before playing this game, you'll need to copy the required "
 				"fonts into ScummVM's extras directory, or into the game directory. "
 				"On Windows, you'll need the following font files from the Windows "
diff --git a/gui/widget.cpp b/gui/widget.cpp
index 2bc374da739..f886e10e1a6 100644
--- a/gui/widget.cpp
+++ b/gui/widget.cpp
@@ -392,6 +392,10 @@ void ButtonWidget::setLabel(const Common::U32String &label) {
 	StaticTextWidget::setLabel(cleanupHotkey(label));
 }
 
+void ButtonWidget::setLabel(const Common::String &label) {
+	ButtonWidget::setLabel(Common::U32String(label));
+}
+
 ButtonWidget *addClearButton(GuiObject *boss, const Common::String &name, uint32 cmd, int x, int y, int w, int h) {
 	ButtonWidget *button;
 
diff --git a/gui/widget.h b/gui/widget.h
index 1de1ebd1bac..a27e53ce78f 100644
--- a/gui/widget.h
+++ b/gui/widget.h
@@ -230,6 +230,7 @@ public:
 	uint32 getCmd() const				{ return _cmd; }
 
 	void setLabel(const Common::U32String &label);
+	void setLabel(const Common::String &label);
 
 	void handleMouseUp(int x, int y, int button, int clickCount) override;
 	void handleMouseDown(int x, int y, int button, int clickCount) override;
diff --git a/gui/widgets/popup.cpp b/gui/widgets/popup.cpp
index af7123fc4af..6bc8f05cc91 100644
--- a/gui/widgets/popup.cpp
+++ b/gui/widgets/popup.cpp
@@ -503,6 +503,10 @@ void PopUpWidget::appendEntry(const U32String &entry, uint32 tag) {
 	_entries.push_back(e);
 }
 
+void PopUpWidget::appendEntry(const String &entry, uint32 tag) {
+	appendEntry(U32String(entry), tag);
+}
+
 void PopUpWidget::clearEntries() {
 	_entries.clear();
 	_selectedItem = -1;
diff --git a/gui/widgets/popup.h b/gui/widgets/popup.h
index a21020690ed..95ed03e35c9 100644
--- a/gui/widgets/popup.h
+++ b/gui/widgets/popup.h
@@ -65,6 +65,7 @@ public:
 	void handleMouseWheel(int x, int y, int direction) override;
 
 	void appendEntry(const U32String &entry, uint32 tag = (uint32)-1);
+	void appendEntry(const String &entry, uint32 tag = (uint32)-1);
 	void clearEntries();
 	int numEntries() { return _entries.size(); }
 
diff --git a/po/module.mk b/po/module.mk
index f8addcd2ad5..e9b885be3bc 100644
--- a/po/module.mk
+++ b/po/module.mk
@@ -1,6 +1,5 @@
 POTFILE := $(srcdir)/po/scummvm.pot
 POFILES := $(wildcard $(srcdir)/po/*.po)
-CPFILES := $(wildcard $(srcdir)/po/*.cp)
 
 ENGINE_INPUT_POTFILES := $(sort $(wildcard $(srcdir)/engines/*/POTFILES))
 updatepot:
@@ -37,12 +36,12 @@ updatepot:
 	fi;
 
 translations-dat: devtools/create_translations
-	devtools/create_translations/create_translations $(POFILES) $(CPFILES)
+	devtools/create_translations/create_translations $(POFILES)
 	mv translations.dat $(srcdir)/gui/themes/
 
-update-translations: updatepot $(POFILES) $(CPFILES) translations-dat
+update-translations: updatepot $(POFILES) translations-dat
 
-update-translations: updatepot $(POFILES) $(CPFILES)
+update-translations: updatepot $(POFILES)
 	@$(foreach file, $(POFILES), echo -n $(notdir $(basename $(file)))": ";msgfmt --statistic $(file);)
 	@rm -f messages.mo