scholarly journals Neural Correlates of Individual Differences in Speech Categorization: Evidence from Subcortical, Cortical, and Behavioral Measures

2021 ◽  
Author(s):  
Jinghua Ou ◽  
Alan Yu

Categorization is a fundamental cognitive ability to group different objects as the same. This ability is particularly indispensable for human speech perception, yet individual differences in speech categorization are nonetheless ubiquitous. The present study investigates the neurophysiological mechanisms underlying the variability in categorization of voice-onset time (VOT). Subcortical and cortical speech-evoked responses are recorded to investigate speech representations at two functional levels of auditory processing. Individual differences in psychometric functions correlate positively with how faithfully subcortical responses encode VOT differences. Moreover, individuals also differ in how strongly the subcortical and cortical representations correlate with each other. Listeners with gradient categorization show higher correspondences between the two representations, indicating that acoustic information is relayed faithfully from the subcortical to the cortical level; listeners with discrete categorization exhibit decreased similarity between the two representations, suggesting that the subcortical acoustic encoding is transformed at the cortical level to reflect phonetic category information.

1991 ◽  
Vol 90 (5) ◽  
pp. 2441-2449 ◽  
Author(s):  
Donal G. Sinex ◽  
Lynn P. McDonald ◽  
John B. Mott

Languages ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 61
Author(s):  
Lisa Kornder ◽  
Ineke Mennen

The purpose of this investigation was to trace first (L1) and second language (L2) segmental speech development in the Austrian German–English late bilingual Arnold Schwarzenegger over a period of 40 years, which makes it the first study to examine a bilingual’s speech development over several decades in both their languages. To this end, acoustic measurements of voice onset time (VOT) durations of word-initial plosives (Study 1) and formant frequencies of the first and second formant of Austrian German and English monophthongs (Study 2) were conducted using speech samples collected from broadcast interviews. The results of Study 1 showed a merging of Schwarzenegger’s German and English voiceless plosives in his late productions as manifested in a significant lengthening of VOT duration in his German plosives, and a shortening of VOT duration in his English plosives, closer to L1 production norms. Similar findings were evidenced in Study 2, revealing that some of Schwarzenegger’s L1 and L2 vowel categories had moved closer together in the course of L2 immersion. These findings suggest that both a bilingual’s first and second language accent is likely to develop and reorganize over time due to dynamic interactions between the first and second language system.


2021 ◽  
pp. 026765832110089
Author(s):  
Daniel J Olson

Featural approaches to second language phonetic acquisition posit that the development of new phonetic norms relies on sub-phonemic features, expressed through a constellation of articulatory gestures and their corresponding acoustic cues, which may be shared across multiple phonemes. Within featural approaches, largely supported by research in speech perception, debate remains as to the fundamental scope or ‘size’ of featural units. The current study examines potential featural relationships between voiceless and voiced stop consonants, as expressed through the voice onset time cue. Native English-speaking learners of Spanish received targeted training on Spanish voiceless stop consonant production through a visual feedback paradigm. Analysis focused on the change in voice onset time, for both voiceless (i.e. trained) and voiced (i.e. non-trained) phonemes, across the pretest, posttest, and delayed posttest. The results demonstrated a significant improvement (i.e. reduction) in voice onset time for voiceless stops, which were subject to the training paradigm. In contrast, there was no significant change in the non-trained voiced stop consonants. These results suggest a limited featural relationship, with independent voice onset time (VOT) cues for voiceless and voices phonemes. Possible underlying mechanisms that limit feature generalization in second language (L2) phonetic production, including gestural considerations and acoustic similarity, are discussed.


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