Deborah G. H. James, Wendy A. Ferguson, Andrew Butcher

Sometimes, children's speech is judged as typical on picture-naming tests and not on other speech tests, even other picture-naming tests. This study attempts to explain this observation by examining the impact of increasing the numbers of polysyllabic words in a picture-naming test on the outcomes of percentages of consonants and vowels correct and phonological processes. The participants were 283 randomly sampled, typically-developing children, aged 3-7-years. These Australian English speakers named pictures, yielding ∼166 selected words, varied for syllable number, stress and shape, which repeatedly sampled all consonants and vowels of Australian English. Most mismatches occurred in di- and polysyllabic words, with few in monosyllabic words: the usual words in picture-naming speech tests. Significant age effects existed for percentages of consonants and vowels correct and for 12 of the 16 phonological processes investigated. Many age effects were present at 7 years; later than often reported. These findings imply that additional di- and polysyllabic words add value to routine speech testing. Further, children, especially school children, who "pass" speech tests dominated by monosyllabic words may benefit from further examination of their productions of di- and polysyllabic words before finalizing clinical judgements about their speech status.