Exploring the variable effects of frequency and semantic diversity as predictors for a word's ease of acquisition in different word classes

Infant vocabulary development is inevitably dependent on the speech they hear in their environment. This paper reports an investigation of the vocabulary statistics that predict a word’s age of acquisition, focusing on frequency and contextual diversity as derived from child-directed speech data along with associative norms generated by adults. Age of acquisition is operationalised using parental-report of infant word knowledge in a British English-speaking population. The work can be considered an extension of Hills, Maouene, Riordan, and Smith (2010) using a fully British English dataset. We found significant effects of both word frequency and word associations on age of acquisition. Interestingly, the strength of these predictors differed between word classes, with frequency being the strongest predictor for nouns and associations the strongest predictor for function words.