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+_These instructions are incomplete and anyone interested in contributing is invited to discuss on [the TeX-hyphen mailing list](http://tug.org/mailman/listinfo/tex-hyphen)_
+
+# Contributing pattern files for an existing language.
+
+If you want to modify patterns for a language that already exists in our
+repository, you should make sure that your additions don’t interfere with the
+current patterns.  It’s not recommended to manually add patterns to a list
+generated by `patgen`: instead, modifications should be made in the hyphenated
+word list that was used as a source, and the full set should be regenerated.
+This of course does not apply to hand-generated patterns.