Assembly: Microsoft.Office.Interop.Word (in microsoft.office.interop.word.dll)
Dictionary objects that represent custom dictionaries are members of the Dictionaries collection. Other dictionary objects are returned by properties of the Language collection; these include the ActiveSpellingDictionary, ActiveGrammarDictionary, ActiveThesaurusDictionary, and ActiveHyphenationDictionary properties. You can use these properties for each language for which proofing tools are installed.
Use CustomDictionaries(index), where index is an index number or the string name for the dictionary, to return a single Dictionary object that represents a custom dictionary.
Use the ActiveCustomDictionary property to set the custom spelling dictionary in the collection to which new words are added. If you try to set this property to a dictionary that's not a custom dictionary, an error occurs.
Use the Add method to add a new dictionary to the collection of active custom dictionaries. If there's no file with the specified name, Microsoft Word creates it.
Use the LanguageSpecific property to determine whether the specified custom dictionary can have a specific language assigned to it with the LanguageID property. If the dictionary is language specific, it will verify only text that's formatted for the specified language.
The ReadOnly property returns True for .lex files (built-in proofing dictionaries) and False for .dic files (custom spelling dictionaries).