Effects of language experience on pre-categorical perception: Distinguishing general from specialized processes in speech perception

The influence of oral language environment on auditory development

OBJECTIVE

The purpose of this study was to compare the auditory processing of hearing children who were immersed in an oral language environment during early childhood with that of children who were poorly exposed to oral language during the same period.

METHODS

Sixty children aged between 5 and 10 years participated in this study. They were divided in two groups. Group 1 comprised of 30 children who had deaf signer parents, and Group 2 comprised of 30 children who had hearing parents. These children underwent the following auditory processing tests: Pediatric Speech Intelligibility, Dichotic Digits, Pitch Pattern Sequence, Gaps-in-Noise, and Memory Tests for Instrumental and Verbal sounds.

RESULTS

Group 1 had significantly poorer performance than that of Group 2 in all tests. In addition, an analysis by age range revealed that the differences between groups were more pronounced in younger children (5-6 years).

CONCLUSION

The results indicate that the development of auditory skills is strongly influenced by access to oral linguistic sounds. Thus, a child's exposure to an oral language environment from birth is important to the adequate development of the auditory system functions.

From speech and talkers to the social world: The neural processing of human spoken language

Human speech perception is a paradigm example of the complexity of human linguistic processing; however, it is also the dominant way of expressing vocal identity and is critically important for social interactions. Here, I review the ways that the speech, the talker, and the social nature of speech interact and how this may be computed in the human brain, using models and approaches from nonhuman primate studies. I explore the extent to which domain-general approaches may be able to account for some of these neural findings. Finally, I address the importance of extending these findings into a better understanding of the social use of speech in conversations.

Differential sensitivity to changes in pitch acceleration in the auditory brainstem and cortex

The cortical pitch-specific response (CPR) is differentially sensitive to pitch contours varying in rate of acceleration-time-variant Mandarin Tone2 (T2) versus constant, linear rising ramp (Linear)-as a function of language experience (Krishnan, Gandour, & Suresh, 2014). CPR and brainstem frequency following response (FFR) data were recorded concurrently from native Mandarin listeners using the same stimuli. Results showed that T2 elicited larger responses than Linear at both cortical and brainstem levels (CPR: Na-Pb, Pb-Nb; FFR). However, Pb-Nb exhibited a larger difference in magnitude between T2 and Linear than either Na-Pb or FFR. This finding highlights differential weighting of brain responses elicited by a specific temporal attribute of pitch. Consistent with the notion of a distributed, integrated hierarchical pitch processing network, temporal attributes of pitch are differentially weighted by subcortical and cortical level processing.