Relationships between native and non-native speech perception.

Abstract

Individuals differ in their ability to perceive and learn unfamiliar speech sounds, but we lack a comprehensive theoretical account that predicts individual differences in this skill. Predominant theories largely attribute difficulties of non-native speech perception to the relationships between non-native speech sounds/contrasts and native-language categories. The goal of the current study was to test whether the predictions made by these theories can be extended to predict individual differences in naive perception of non-native speech sounds or learning of these sounds. Specifically, we hypothesized that the internal structure of native-language speech categories is the cause of difficulty in perception of unfamiliar sounds such that learners who show more graded (i.e., less categorical) perception of sounds in their native language would have an advantage for perceiving non-native speech sounds because they would be less likely to assimilate unfamiliar speech tokens to their native-language categories. We tested this prediction in two experiments in which listeners categorized speech continua in their native language and performed tasks of discrimination or identification of difficult non-native speech sound contrasts. Overall, results did not support the hypothesis that individual differences in categorical perception of native-language speech sounds is responsible for variability in sensitivity to non-native speech sounds. However, participants who responded more consistently on a speech categorization task showed more accurate perception of non-native speech sounds. This suggests that individual differences in non-native speech perception are more related to the stability of phonetic processing abilities than to individual differences in phonetic category structure.

Exploring individual differences in native phonetic perception and their link to nonnative phonetic perception.

“…Very recent work by Fuhrmeister et al (2023) is in line with our findings. Similarly to us, the authors hypothesized that more gradient VAS slopes on a native phonetic perception task would relate to better discrimination of nonnative phonemes; and yet they found that more consistent VAS responses related to better nonnative discrimination.…”

“…The present work and work by Fuhrmeister et al (2023) suggest that nonnative perception is predicted by the consistency of native perception. If this finding continues to be replicated, it could provide an exciting avenue for further exploration.…”

“…Although our preregistered analyses revealed a somewhat surprising lack of evidence for a relationship between native and nonnative perception, similar findings have been reported in the past. For instance, other work has found that gradiency of native perception on a VAS task did not relate to nonnative discrimination ability (Fuhrmeister et al, 2023) or to scores on a standardized nonnative proficiency task (Kong & Kang, 2022). It may be that native gradiency does not relate strongly to nonnative outcomes due to differences in some of the processing strategies involved.…”

“…Conversely, steeper identification slopes on 2AFC tasks might predict better nonnative perception, since an optimal strategy for a gradient listener on such tasks could be to clearly label each sound based on whichever category it best fits (as discussed above). Fuhrmeister et al (2023) recently studied nonnative discrimination ability and native gradiency as measured by a VAS task and were surprised not to find evidence for a relationship between the two. Instead they found that nonnative discrimination related to the consistency of VAS responses, that is, how similar participants' ratings were across trials for a given stimulus.…”

“…Greater SD of residuals reflects less consistent responses. This is the same method used by Kapnoula et al (2017) to calculate consistency, and closely resembles the method used by Fuhrmeister et al (2023) who also calculated residuals from a logistic function fit to participants' VAS responses (but theirs was a regular rather than a rotated logistic function, since their continua varied only along one acoustic dimension).…”