VOWEL PERCEPTION IN CHILDREN WITH AND WITHOUT LANGUAGE IMPAIRMENT

Twenty-four children with language impairment (LI) and 22 children wit hout language impairment (LN) participated in a study of discriminatio n, identification, and serial ordering of the highly dissimilar vowels /a/ versus /i/, and the highly similar vowels /epsilon/ versus /ae/. The vowel pairs were presented to the subjects in long- and short-dura tion sets. Both groups had greater difficulty in identifying /epsilon/ versus ae/ than /a/ versus /i/. Neither group had greater difficulty with the short- than the long-duration vowel sets. The LI children wer e less efficient than the LN in identifying /a/ versus /i/, but could identify them accurately. They were significantly less accurate than t he LN in identifying /epsilon/ versus /dipthong ae>/. The majority of the children who could identity the /a/ and /i/ vowels were able to or der them serially as well, although this second task appeared to be mo re difficult than identification. Fewer LI than LN children were able to proceed to the serial ordering task with /epsilon/ and /dipthong ae >/. The children who could not identify the vowels within a set were a lmost always able to discriminate them. It was concluded that LI child ren have an auditory perceptual learning deficit and consequently a le ss robust central representation for steady state vowels than LN.