Two-year-olds' phonological acquisition: Normative data.

The study reported evaluated an assessment of phonology for 2-year-olds to establish normative data and determine if early identification of children with speech difficulties is possible. The study evaluated 62 2-year-old children on the Toddler Phonology Test (TPT). Children produced 32 words, spontaneously or in imitation. Ten of the children were assessed three times, on the third occasion, when they had reached 3 years, on another phonological assessment. The data indicated that older children performed better than younger children on quantitative measures. Girls and boys performed equally well. Their phonetic repertoires were missing some fricatives and all affricates, as well as /r/. Consistently used error patterns identified included cluster reduction, final consonant deletion, stopping, fronting, weak syllable, deletion, gliding and deaffrication. Correlation analyses indicated that performance at the first assessment on the TPT indicated performance on subsequent assessments. While quantitative data was not a reliable predictive indicator of speech disorder, qualitative analysis of error types was predictive, with children who made many atypical errors at 2 years being diagnosed as phonologically disordered at 3 years. The findings provide initial evidence that direct formal assessment of 2-year-old phonology is possible.