Speech perception, phonological sensitivity, and articulation in early vocabulary development

Sammanfattning: Speech perception, articulation, and word learning are three major tiers of language development in young children, integrating perceptual and productive language abilities. Infant speech perception precedes speech production and is the basis for native language learning. In speech production, children refine their articulation skills beginning with their first vocalic utterances until they reach adult performance level. The third tier describes children’s vocabulary development from their first words to their established receptive and productive lexicon after the vocabulary spurt. Speech perception, articulation, and word learning interact at the level of lexical representations.By investigating the relationship between the attention to phonological detail in speech and word learning, the degree of phonological detail in the lexical representations can be inferred. This relationship can be described by two models: the vocabulary-driven and phonology-driven model. The vocabulary-driven model proposes that the structure of the lexicon influences attention to phonological detail in speech perception, and this model is consistent with the Lexical Restructuring Model. On the other hand the phonology-driven model proposes that vocabulary increases as a result of increased attention to phonological detail in speech.To infer the phonological specifications of lexical representations of words in 2½- to 3-year-olds, the variables vocabulary, phonological sensitivity, language-specific speech perception and articulation accuracy were tested in a longitudinal study with 60 participants. For these variables, new measures were developed, adapted, and tested. It was found that phonological sensitivity at 30 months predicted vocabulary at 33 months, but not the opposite. This supports the prediction of the phonology-driven model. However, in an augmented version of the vocabulary-driven model that included all variables, articulation at 30 months was found to predict phonological sensitivity at 33 months. These results are discussed in the light of the Lexical Restructuring Model, and the interaction of speech perception, articulation skills, and lexical representations, and suggestions for future research are offered.