Assessing speech perception in children with language difficulties: effects of background noise and phonetic contrast

Deficits in speech perception are reported for some children with language impairments. This deficit is more marked when listening against background noise. This study investigated the speech perception skills of young children with and without language difficulties. A speech discrimination task, using non-word minimal pairs in an XAB paradigm, was presented to 20 5-7-year-old children with language difficulties and 33 typically-developing (TD) children aged between 4- to 7-years. Stimuli were presented in quiet and in background noise (babble), and stimuli varied in phonetic contrasts, differing in either place of articulation or presence/absence of voicing. Children with language difficulties performed less well than TD children in all conditions. There was an interaction between group and noise condition, such that children with language difficulties were more affected by the presence of noise. Both groups of children made more errors with one voicing contrast /s z/ and there was some indication that children with language difficulties had proportionately greater difficulty with this contrast. Speech discrimination scores were significantly correlated with language scores for children with language difficulties. Issues in developing material for assessment of speech discrimination in children with LI are discussed.