Listeners' adaptation to unreliable intonation is speaker-sensitive

Evidence For Selective Adaptation and Recalibration in the Perception of Lexical Stress

Individuals vary in how they produce speech. This variability affects both the segments (vowels and consonants) and the suprasegmental properties of their speech (prosody). Previous literature has demonstrated that listeners can adapt to variability in how different talkers pronounce the segments of speech. This study shows that listeners can also adapt to variability in how talkers produce lexical stress. Experiment 1 demonstrates a selective adaptation effect in lexical stress perception: repeatedly hearing Dutch trochaic words biased perception of a subsequent lexical stress continuum towards more iamb responses. Experiment 2 demonstrates a recalibration effect in lexical stress perception: when ambiguous suprasegmental cues to lexical stress were disambiguated by lexical orthographic context as signaling a trochaic word in an exposure phase, Dutch participants categorized a subsequent test continuum as more trochee-like. Moreover, the selective adaptation and recalibration effects generalized to novel words, not encountered during exposure. Together, the experiments demonstrate that listeners also flexibly adapt to variability in the suprasegmental properties of speech, thus expanding our understanding of the utility of listener adaptation in speech perception. Moreover, the combined outcomes speak for an architecture of spoken word recognition involving abstract prosodic representations at a prelexical level of analysis.

Interlocutor modelling in comprehending speech from interleaved interlocutors of different dialectic backgrounds

It has been shown that, in language comprehension, listeners model certain attributes of their interlocutor (e.g., dialectic background, age, gender) and interpret speech against that model; for example, they understand cross-dialectally ambiguous words such as flat and gas for their American English (AE) meanings more often when listening to an AE interlocutor than a British English (BE) interlocutor. This study further investigated whether listeners construct concurrent interlocutor models when communicating with interleaved interlocutors of different dialectic backgrounds, and, if they do, how they choose between concurrent models to interpret words. In two experiments, participants heard a word (e.g., flat) spoken by a BE or AE interlocutor and provided a word associate (indicating which meaning of the word was accessed). When different interlocutors were encountered in separate blocks, participants accessed more AE meanings when listening to an AE rather than a BE interlocutor, and the accent effect was not larger for words pronounced more differently in BE and AE (e.g., fall sounds more distinctly British vs. American than flat does). These results suggest that participants constructed an interlocutor model (e.g., of a BE or an AE speaker) and used it (instead of accent details in a word) to guide word meaning access. When interlocutors were interleaved in the same block, we observed a comparable accent effect, which increased as a function of between-accent differences in pronunciation. These results suggest that participants constructed concurrent interlocutor models and used accent details in a word to select the appropriate interlocutor model. We also observed that the accent effect was comparable for two interleaved interlocutors of the same gender (e.g., a female BE interlocutor and a female AE interlocutor) and for two interleaved interlocutors of different genders (e.g., a female BE interlocutor and a male AE interlocutor). These results suggest that participants did not use gender-related voice details for model selection when accent details were sufficient for interlocutor model selection.

Thinking probabilistically in the study of intonational speech prosody

Speech prosody, the melodic and rhythmic properties of a language, plays a critical role in our everyday communication. Researchers have identified unique patterns of prosody that segment words and phrases, highlight focal elements in a sentence, and convey holistic meanings and speech acts that interact with the information shared in context. The mapping between the sound and meaning represented in prosody is suggested to be probabilistic-the same physical instance of sounds can support multiple meanings across talkers and contexts while the same meaning can be encoded in physically distinct sound patterns (e.g., pitch movements). The current overview presents an analysis framework for probing the nature of this probabilistic relationship. Illustrated by examples from the literature and a dataset of German focus marking, we discuss the production variability within and across talkers and consider challenges that this variability imposes on the comprehension system. A better understanding of these challenges, we argue, will illuminate how the human perceptual, cognitive, and computational mechanisms may navigate the variability to arrive at a coherent understanding of speech prosody. The current paper is intended to be an introduction for those who are interested in thinking probabilistically about the sound-meaning mapping in prosody. Open questions for future research are discussed with proposals for examining prosodic production and comprehension within a comprehensive, mathematically-motivated framework of probabilistic inference under uncertainty. This article is categorized under: Linguistics > Language in Mind and Brain Psychology > Language.

Adaptation in Predictive Prosodic Processing in Bilinguals

Native language listeners engage in predictive processing in many processing situations and adapt their predictive processing to the statistics of the input. In contrast, second language listeners engage in predictive processing in fewer processing situations. The current study uses eye-tracking data from two experiments in bilinguals’ native language (L1) and second language (L2) to explore their predictive processing based on contrastive pitch accent cues, and their adaptation in the face of prediction errors. The results of the first experiment show inhibition effects for unpredicted referents in both the L1 and the L2 that can be modeled with a Bayesian adaptation model, suggesting that bilinguals adapt their prediction in the face of prediction errors in a way that is compatible with the model. In contrast, the results of the second experiment, after a training phase that increased the predictive validity of the cue, show inhibition effects for unpredicted referents only in the L1, but not in the L2. In addition, the Bayesian adaptation model significantly predicts only the L1, but not the L2 data. The results are discussed with respect to adaptation to the statistical properties of the input.