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verbDictionary Validity
- Tournament Word List (TWL)
- SCRABBLE US
- Collins Scrabble Words (CSW21)
- SCRABBLE UK
- ENABLE Dictionary
- WORDS WITH FRIENDS
- Combined US/UK Scrabble Dictionary
- SOWPODS
- North American Scrabble (NWL2020)
- NASPA
Source: Google Books Ngram Viewer (1800–2019)