Domain-general mechanisms for speech segmentation: The role of duration information in language learning.

Rebecca L A Frost,Padraic Monaghan,Tomoko Tatsumi

doi:10.1037/xhp0000325

Abstract

Speech segmentation is supported by multiple sources of information that may either inform language processing specifically, or serve learning more broadly. The Iambic/Trochaic Law (ITL), where increased duration indicates the end of a group and increased emphasis indicates the beginning of a group, has been proposed as a domain-general mechanism that also applies to language. However, language background has been suggested to modulate use of the ITL, meaning that these perceptual grouping preferences may instead be a consequence of language exposure. To distinguish between these accounts, we exposed native-English and native-Japanese listeners to sequences of speech (Experiment 1) and nonspeech stimuli (Experiment 2), and examined segmentation using a 2AFC task. Duration was manipulated over 3 conditions: sequences contained either an initial-item duration increase, or a final-item duration increase, or items of uniform duration. In Experiment 1, language background did not affect the use of duration as a cue for segmenting speech in a structured artificial language. In Experiment 2, the same results were found for grouping structured sequences of visual shapes. The results are consistent with proposals that duration information draws upon a domain-general mechanism that can apply to the special case of language acquisition.

Highlights

Speech segmentation is supported by multiple sources of information that may either inform language processing or serve learning more broadly
For English listeners, the results replicated previous studies demonstrating the benefit of final-syllable duration increase for identifying word boundaries in speech, where word boundaries are defined in terms of transitional probabilities between syllables (Saffran et al, 1996)
The linear effect of cue condition showed that increasing the duration of the initial syllable had a slight detrimental effect on identifying word boundaries compared with the other conditions, whereas increasing the duration of the final syllable meant that such boundaries were isolated more accurately compared with when no duration cue was present in the speech

Summary

Introduction

Speech segmentation is supported by multiple sources of information that may either inform language processing or serve learning more broadly. Language background has been suggested to modulate use of the ITL, meaning that these perceptual grouping preferences may instead be a consequence of language exposure. To distinguish between these accounts, we exposed native-English and native-Japanese listeners to sequences of speech (Experiment 1) and nonspeech stimuli (Experiment 2), and examined segmentation using a 2AFC task. Public Significance Statement This study shows that adults prefer to group both sequences of shapes and sequences of speech with the final item as the one that has the longest duration This suggests that final-item duration increase is a helpful cue for perceptual grouping in multiple domains—not just language processing.

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