DictionaryLookup Source Information
DictionaryLookupData is based on a wide range of sources, with enhancement at the Wolfram Research Companies by both human and algorithmic processing. DictionaryLookupData is continually maintained with the latest available information, with automatic updating when DictionaryLookupData is used inside Mathematica.
Among principal sources for DictionaryLookupData are:
Atkinson, K. "GNU Aspell." 2004. »
International Business Machines Corporation et al. "International Components for Unicode." 2008. »