Does frequency count? Parental input and the acquisition of vocabulary

TLDR

Studies on vocabulary acquisition usually focus on a single lexical category or a limited set of words. The study evaluates how parental input frequency relates to age of acquisition across a large word sample. The authors used CDI norming data for 562 words and CHILDES frequency estimates from parent‑child interactions to analyze the relationship. Higher parental frequency predicts later acquisition for production overall, but earlier acquisition within categories, and only common nouns show a comprehension effect; frequency effects vary across development, indicating a complex interaction with category, modality, and age.

Abstract

ABSTRACT Studies examining factors that influence when words are learned typically investigate one lexical category or a small set of words. We provide the first evaluation of the relation between input frequency and age of acquisition for a large sample of words. The MacArthur-Bates Communicative Development Inventory provides norming data on age of acquisition for 562 individual words collected from the parents of children aged 0 ; 8 to 2 ; 6. The CHILDES database provides estimates of frequency with which parents use these words with their children (age: 0 ; 7–7 ; 5; mean age: 36 months). For production, across all words higher parental frequency is associated with later acquisition. Within lexical categories, however, higher frequency is related to earlier acquisition. For comprehension, parental frequency correlates significantly with the age of acquisition only for common nouns. Frequency effects change with development. Thus, frequency impacts vocabulary acquisition in a complex interaction with category, modality and developmental stage.