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The present study provides evidence of a positive correlation between L1 and L2 intelligibility for bilingual talkers. Each talker in a group of Mandarin-English and Korean-English bilinguals was recorded producing simple sentences in each of their languages. The recordings were then presented to native listeners of the language-being-spoken in a test of sentence-in-noise recognition to yield a pair of L1 and L2 intelligibility scores for each talker based on the proportion of words correctly recognized. For all talkers, their L2 speech (i.e., Mandarin- or Korean-accented English) was consistently lower in intelligibility than their L1 speech (i.e., native accented Mandarin or Korean). This dissociation between L1-L2 speech intelligibility was evident in different intelligibility scores at comparable signal-to-noise ratios (as much as 35 percentage points for the Mandarin-English bilinguals) and in the required boost in signal-to-noise ratio to achieve comparable intelligibility (>8–10 dB). Critically, L1 and L2 intelligibility scores within the bilingual talkers were strongly positively correlated: Talkers with relatively high intelligibility in L1 also achieved relatively high intelligibility in L2. These results indicate a persistent influence of talker-specific trait characteristics that combine with, rather than are overwhelmed by, language-specific and dominance-dependent influences in bilingual speech production.

Prior research has demonstrated that listeners are sensitive to changes in the indexical (talker-specific) characteristics of speech input, suggesting that these signal-intrinsic features are integrally encoded in memory for spoken words. Given that listeners frequently must contend with concurrent environmental noise, to what extent do they also encode signal-extrinsic details? Native English listeners’ explicit memory for spoken English monosyllabic and disyllabic words was assessed as a function of consistency versus variation in the talker’s voice (talker condition) and background noise (noise condition) using a delayed recognition memory paradigm. The speech and noise signals were spectrally-separated, such that changes in a simultaneously presented non-speech signal (background noise) from exposure to test would not be accompanied by concomitant changes in the target speech signal. The results revealed that listeners can encode both signal-intrinsic talker and signal-extrinsic noise information into integrated cognitive representations, critically even when the two auditory streams are spectrally non-overlapping. However, the extent to which extra-linguistic episodic information is encoded alongside linguistic information appears to be modulated by syllabic characteristics, with specificity effects found only for monosyllabic items. These findings suggest that encoding and retrieval of episodic information during spoken word processing may be modulated by lexical characteristics.

In this study, we consider how native status and signal degradation influence French listeners’ segmentation of an incoming speech stream containing liaison , a phonological process that misaligns word and syllable boundaries. In particular, we investigate how both first language (L1) and second language (L2) French listeners compensate for the syllable-word misalignment associated with liaison while segmenting French speech, and whether compensation-for-liaison strategies differ with decreasing signal-to-noise ratios. We consider the degree to which listeners rely on lexical knowledge, acoustic-phonetic cues, and distributional information to accomplish this compensation. Listeners completed a word identification task in which they heard adjective-noun sequences with or without liaison and were presented with the word or nonword alternatives for each noun that would result depending on whether the listener did or did not compensate for liaison. Results showed that both L1-French and L2-French listeners generally preferred lexically acceptable parses over those that resulted in a stranded nonword, and both groups gave significantly fewer lexically acceptable parses under harder listening conditions. However, the L2-French listeners demonstrated a pattern of boundary placement that indicated over-compensation for liaison, suggesting that they had successfully acquired, but not fully constrained, rules about liaison.

This study explores phonetic convergence during conversations between pairs of talkers with varying language distance. Specifically, we examined conversations within two native English talkers and within two native Korean talkers who had either the same or different regional dialects, and between native and nonnative talkers of English. To measure phonetic convergence, an independent group of listeners judged the similarity of utterance samples from each talker through an XAB perception test, in which X was a sample of one talker's speech and A and B were samples from the other talker at either early or late portions of the conversation. The results showed greater convergence for same-dialect pairs than for either the different-dialect pairs or the different-L1 pairs. These results generally support the hypothesis that there is a relationship between phonetic convergence and interlocutor language distance. We interpret this pattern as suggesting that phonetic convergence between talker pairs that vary in the degree of their initial language alignment may be dynamically mediated by two parallel mechanisms: the need for intelligibility and the extra demands of nonnative speech production and perception.