Adding new words to the en-US dictionary

Occasionally bugs are filed pointing out situations where perfectly legitimate words are missing from the English spell check dictionary in Firefox. This article describes the process for adding a word to the dictionary.

The process is pretty straight-forward:

  1. Get a clone of mozilla-central (see Firefox Contributors’ Quick Reference), if you don’t already have one, and make sure you can build it successfully.

  2. Get into the dictionary sources directory using this command: cd extensions/spellcheck/locales/en-US/hunspell/dictionary-sources

  3. There’s a special script used for editing dictionaries. The script only works if you have the environment variable EDITOR set to the executable of an editor program; if you don’t have it set, you can use EDITOR=vim sh edit-dictionary to edit using vim (or you can substitute some other editor), or you can just type sh edit-dictionary if you have an EDITOR already specified.

  4. Add and remove words in the dictionary file, then quit the editor.

  5. Use sh merge-dictionaries to process the dictionary changes you’ve made.

  6. Move the revised dictionary file into position: mv en-US.dic ..

  7. Build Firefox and test your updated dictionary. Once you’re satisfied, use the process described in To write a patch to create a patch.