Word characteristics of late talkers’ early lexicon

Toddlers with smaller vocabulary than expected for their age are considered late talkers (LT). This study explored the effects of characteristics of words on vocabulary acquisition of 12- to 24-month-old LT children compared with an age matched (AM) and a vocabulary matched (VM) group of typically developing peers. Using the Hebrew-MacArthur-Bates-Communicative Development Inventory questionnaire, words were rated by adults for babiness, concreteness and iconicity and scored for phonological complexity. The effects of the characteristics of the words on their acquisition were examined. Results showed that the vocabulary of the toddlers from all three groups consisted of words that are more relevant to a child’s world and experience (babiness), more concrete, more phonologically simple, and more iconic. When LT children were compared to AM children, the characteristics of their vocabulary were different in terms of structure (e.g., iconicity) and meaning (e.g., concreteness), but similar in phonological complexity and babiness. When they were compared to VM peers, the vocabulary characteristics of LT children were similar, though they used words that were less related to babies’ world. The parallel patterns found for LT and VM children versus AM children suggest that LT children’s vocabularies differ from those of their age-matched peers due to their smaller size and not due to structural differences. The implications for theory and clinic are discussed.