7.6 Affix Compression

Aspell, as of version 0.60, now has support for affix compression. The codebase comes from MySpell found in OpenOffice.

To add support for affix compression add the following lines to the language data file.

affix          lang
affix-compress true

The line ‘affix lang’ adds support for recognizing affix information, and the line ‘affix-compress true’ enables affix compression.

The affix file is expected to be named ‘lang_affix.dat’. It is the exact same format as those used by MySpell. More information can be found in the myspell/ directory of the distribution or at http://lingucomponent.openoffice.org/dictionary.html.

Affix compression can also be used with soundslike lookup. Aspell does this by only storing the soundslike for the root word. When a word is misspelled it will search for a soundslike close to all possible roots of the misspelled word.

When no soundslike information, or the simple soundslike, is used it may be beneficial to specify the option ‘partially-expand’ which will partially expand a word with affix information so that the affix flags do not affect the first 3 letters of the word. This will allow Aspell to get more accurate results when scanning the list for near misses since the full word can be used and not just the root. Specifying this option, however, will also effectively expand any prefixes. Thus this option should not be used for prefix heavy languages such as Hebrew.

An existing word list, without affix info, can be affix compressed using using aspell munch-list.