Teacher ratings of children's listening difficulties

Infants' early phonetic perception is hypothesized to play an important role in language development. Previous studies have not assessed this potential link in the first 2 years of life. In this study, speech discrimination was measured in 6-month-old infants using a conditioned head-turn task. At 13, 16, and 24 months of age, language development was assessed in these same children using the MacArthur Communicative Development Inventory. Results demonstrated significant correlations between speech perception at 6 months of age and later language (word understanding, word production, phrase understanding). The finding that speech perception performance at 6 months predicts language at 2 years supports the idea that phonetic perception may play an important role in language acquisition. Copyright 2004 Society for Research in Child Development, Inc.

Poor readers are inferior to normal-reading peers in aspects of speech perception. Two hypotheses have been proposed to account for their deficits: (i) a speech-specific failure in phonological representation and (ii) a general deficit in auditory "temporal processing," such that they cannot easily perceive the rapid spectral changes of formant transitions at the onset of stop-vowel syllables. To test these hypotheses, two groups of second-grade children (20 "good readers," 20 "poor readers"), matched for age and intelligence, were selected to differ significantly on a /ba/-/da/ temporal order judgment (TOJ) task, said to be diagnostic of a temporal processing deficit. Three experiments then showed that the groups did not differ in: (i) TOJ when /ba/ and /da/ were paired with more easily discriminated syllables (/ba/-/sa/, /da/-/fa/); (ii) discriminating nonspeech sine wave analogs of the second and third formants of /ba/ and /da/; (iii) sensitivity to brief transitional cues varying along a synthetic speech continuum. Thus, poor readers' difficulties with /ba/-/da/ reflected perceptual confusion between phonetically similar, though phonologically contrastive, syllables rather than difficulty in perceiving rapid spectral changes. The results are consistent with a speech-specific, not a general auditory, deficit.

Specific language impairment (SLI) is one of the most common childhood disorders, affecting 7% of children. These children experience difficulties in understanding and producing spoken language despite normal intelligence, normal hearing, and normal opportunities to learn language. The causes of SLI are still hotly debated, ranging from nonlinguistic deficits in auditory perception to high-level deficits in grammar. Here, we show that children with SLI have poorer-than-normal consonant identification when measured in ecologically valid conditions of stationary or fluctuating masking noise. The deficits persisted even in comparison with a younger group of normally developing children who were matched for language skills. This finding points to a fundamental deficit. Information transmission of all phonetic features (voicing, place, and manner) was impaired, although the deficits were strongest for voicing (e.g., difference between/b/and/p/). Children with SLI experienced perfectly normal "release from masking" (better identification in fluctuating than in stationary noise), which indicates a central deficit in feature extraction rather than deficits in low-level, temporal, and spectral auditory capacities. We further showed that speech identification in noise predicted language impairment to a great extent within the group of children with SLI and across all participants. Previous research might have underestimated this important link, possibly because speech perception has typically been investigated in optimal listening conditions using non-speech material. The present study suggests that children with SLI learn language deviantly because they inefficiently extract and manipulate speech features, in particular, voicing. This result offers new directions for the fast diagnosis and remediation of SLI.