Spelling Dictionary Format

The main dictionaries are zip files with a .dct extension. The zip file may contain several word lists, each stored as a UTF-8-encoded text file containing lists of valid words, one per line. All such entries must have a ".words" extension.

Words that start with lowercase characters are assumed to be regular words, which can be used in lower-case or upper-case (for example, "apple," "banana," "cherry"). Words that start with capitals are assumed to be proper names, and are flagged as spelling mistakes if used in lowercase (for example, "Albert," "Bernoulli," "Cantor").

The .dct file may also include a "rules" entry that specifies rules to apply when checking the spelling of text in the dictionary language. For example, the French dictionary that ships with SpellChecker for WPF and Silverlight contains the following rules:

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 are tagged as spelling errors:

h'amour (check 'h'amour': incorrect)
x'amuor (check 'x'amuor': incorrect)

You can create and edit dictionary files using standard applications such as Notepad and WinZip, or you can use the C1DictionaryEditor application that ships with SpellChecker for WPF and Silverlight.