The IntelliSpell control uses up to three dictionaries while checking text:

• Main dictionaries: Read-only dictionary that contains the main word list. The US-English version of this dictionary is built into the control, so there's no need for any additional files.
• User dictionaries: Read-write dictionary used to store words that are correct, but are not part of the main dictionaries. These files are stored as plain UTF-8 text.
• Custom dictionaries: Any .NET object that implements the ISpellDictionary interface. This allows users to create their own dictionary classes, using whatever scheme makes sense in their application. A custom dictionary could, for example, look up words on the Web using a Web service (and then cache them for speed).

Word Lists

The main dictionaries are zip files with a .dct extension. The zip file may contain several word lists, each one stored as a UTF-8-encoded text file containing lists of valid words. All such entries must have a ".words" extension. For information on how to add word lists, see the Editing the Contents of the DCT File and Creating a New DCT File topics.

Rules

The file may also include a "rules" entry that specifies rules to apply when spell-checking text in the dictionary language. For example, the French dictionary that ships with C1SpellChecker contains the following entries:

• IgnorePrefix: l' d' j' da' m' s' n' qu'
• IgnoreSuffix: 's

These tell the spell checker to ignore some common prefixes and suffixes; they are removed before the word is checked. For example:

• l'amour (check 'amour' -> correct)
• l'amuor (check 'amuor' -> incorrect)
• Maxim's (check 'Maxim' -> correct)
• Naxim's (check 'Naxim' -> incorrect)

Prefixes and suffixes not included will be tagged as spelling errors:

• h'amour            (check 'h'amour' -> incorrect)
• x'amuor            (check 'x'amuor' -> incorrect)