Phonetic profiles of toddlers with specific expressive language impairment (SLI-E)

Spontaneous language samples of 30 24-month-old toddlers diagnosed with Specific Expressive Language Impairment (SLI-E) were compared with samples produced by an age-matched group of 30 typically developing toddlers. Vocalization patterns, phonetic inventories, and syllable formation patterns were compared. Toddlers with SLI-E vocalized significantly less often than their typically developing peers, had proportionately smaller consonantal and vowel inventories, and used a more restricted and less mature array of syllable shapes. Although the mean incidence of phoneme usage varied significantly in all comparisons, profiles of consonant usage were similar between the two groups for initial phoneme usage, but considerably different for final consonant closure. Such patterns of vocal and phonetic behavior confirm earlier reports of phonetic delay in SLI-E, and suggest that nongrammatical factors contribute to the development of expressive language deficits in toddlers. We further propose a bidirectional model for the expressive deficits in SLI-E, in which the child's limited phonetic capacity interacts with propensities in caretaker interaction to further reduce opportunities for expressive language learning and practice.