One ubiquitous problem in language processing involves the assignment of words to the correct grammatical category, such as noun or verb. In general, semantic and syntactic cues have been cited as the principal information for grammatical category assignment, to the neglect of possible phonological cues. This neglect is unwarranted, and the following claims are made:(1) Numerous correlations between phonology and grammatical class exist,(2) some of these correlations are large and can pervade the entire lexicon of a language and hence can involve thousands of words,(3) experiments have repeatedly found that adults and children have learned these correlations, and (4) explanations for how these correlations arose can be proposed and evaluated. Implications of these phenonema for language representation and processing are discussed.(PsycINFO Database Record (c) 2016 APA, all rights reserved)