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What do these capital letters mean after the / character in the en-US.dic file found in the \Firefox\Dictionaries folder?

For example:


What does M or MS or GDS, etc. mean? I'm sure there's documentation online somewhere, but I'm not having much luck finding it.

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up vote 6 down vote accepted

The letter identifiers refer to affixes listed in the corresponding .aff file. This prevents the need to list every form of every word in the .dic file. See "Understanding the Affix File Format" for further information.

The same format is used by the MySpell spell checker.

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After searching on this myself I finally found this page with a good explanation.

Each rule is in the .aff file for that language. The rules come in two flavors: SFX for suffixes, and PFX for prefixes. Each line begins with PFX/SFX and then the rule letter identifier (the ones that follow the word in the dictionary file:

PFX [rule_letter_identifier] [combineable_flag] [number_of_rule_lines_that_follow]

You can normally ignore the combinable flag, it is Y or N depending on whether it can be combined with other rules. Then there are some number of lines (indicated by the ) that list different possibilities for how this rule applies in different situations. It looks like this:

PFX [rule_letter_identifier] [number_of_letters_to_delete] [what_to_add] [when_to_add_it]

For example:

  • SFX B Y 3
  • SFX B 0 able [^aeiou]
  • SFX B 0 able ee
  • SFX B e able [^aeiou]e

If "B" is one of the letters following a word, then this is one of the rules that can apply. There are three possibilities that can happen (because there are three lines). Only one will apply:

able is added to the end when the end of the word is "not" (indicated by "^") one of the letters in the set (indicated by "[ ]") of letters a, e, i, o, and u. For example, question → questionable able is added to the end when the end of the word is "ee". For example, agree → agreeable. able is added to the end when the end of the word is not a vowel ("[^aeiou]") followed by an "e". The letter "e" is stripped (the column before able). For example, excite → excitable.

PFX rules are the same, but apply at the beginning of the word instead for prefixes.

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Can you summarize the information at the link within your answer in case the link goes dead? – jonsca Aug 19 '13 at 21:26

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