LAUSR

Abstract This study investigates the influence of semantic maturation on early lexical development by examining the impact of contextual diversity—known to influence semantic development—on word promotion from receptive to productive vocabularies (i.e., comprehension‐expression gap). Study 1 compares the vocabularies of 3685 American‐English‐speaking typical talkers (TTs) and late talkers (LTs; 16–30 months old; 1257 females, 1021 gender unknown; ethnicity unknown; data downloaded in 2018) and finds that LTs, with a longer preverbal phase, produced nouns with lower contextual diversity (R 2 = .80), but verbs with higher contextual diversity (R 2 = .13). Study 2 compares computational network growth models of semantic maturation and finds that verbs require more semantic maturation than nouns, and TTs produce words that are more semantically mature than LTs.