At the end of the first year infants begin to focus on their familiar-sounding native language, and begin to build a receptive and productive vocabulary. Phonological short-term memory has been proposed as an indicator of an individual's
later vocabulary (Gathercole and Baddeley, 1989). This research is an attempt to bring together these different strands of language development by investigating the relationship between word form recognition, word production, comprehension and phonological short-term memory in a longitudinal study.
Word form recognition was determined by the amount of time infants spent looking towards auditorily presented familiar words using the head-tum preference procedure at 10 months. Previous research demonstrated that 11-month-olds look
longer towards familiar words versus unfamiliar words (Depaolis, Vihman & Bywater, 1998). This research begins by replicating these findings (Experiment la) and extending them by testing 10-month-olds (Experiment 1 b ). This age group was found to recognise familiar word patterns. Word production was measured in two ways; by observing and videotaping infants in free play interacting with a caregiver for 30 minutes at 14 and 18 months of age (Experiment 2), and by parental report (the Oxford Communicative Development Inventory was used) at 10, 14, 18 and 24 months (Experiment 3). Speech comprehension was also assessed at these ages with the parental report (Experiment 3). Phonological short-tern memory was measured at 24 months of age using a non-word repetition task (Experiment 4 ).
An interesting developmental overview of language development emerged, suggesting that sensitivity to phonological patterns is an important implicit skill, leading to the formation of stable word representations, and early accurate word
productions. The ease at which infants repeat non-words appears to reflect an infant's sensitivity to word forms and early word production. That is, if an infant was sensitive to phonological patterns and recognised familiar words at 10 months, they were found to be effective, and early, word producers with high non-word repetition scores at 24 months. From these findings it is feasible to propose that sensitivity to phonological patterns could predict later language development.