Purpose: In this study, the authors looked for effects of vocal practice on phonological working memory.
Method: A longitudinal design was used, combining both naturalistic observations and a nonword repetition test. Fifteen 26-month-olds (12 of whom were followed from age 11 months) were administered a nonword test including real words, "standard" nonwords (identical for all children), and nonwords based on individual children's production inventory (in and out words).
Results: A strong relationship was found between (a) length of experience with consonant production and (b) nonword repetition and between (a) differential experience with specific consonants through production and (b) performance on the in versus out words.
Conclusions: Performance depended on familiarity with words or their subunits and was strongest for real words, weaker for in words, and weakest for out words. The results demonstrate the important role of speech production in the construction of phonological working memory.