Coping with gradient forms of /t/-deletion and lexical ambiguity in spoken word recognition

This study investigates how listeners cope with gradient forms of deletion of word-final /t/ when recognising words in a phonological context that makes /t/-deletion viable. A corpus study confirmed a high incidence of /t/-deletion in an /st#b/ context in Dutch. A discrimination study showed that differences between released /t/, unreleased /t/ and fully deleted /t/ in this specific /st#b/ context were salient. Two on-line experiments were carried out to investigate whether lexical activation might be affected by this form variation. Even though unreleased and released variants were processed equally fast by listeners, a detailed analysis of the unreleased condition provided evidence for gradient activation. Activating a target ending in /t/ is slowest for the most reduced variant because phonological context has to be taken into account. Importantly, activation for a target with /t/ in the absence of cues for /t/ is reduced if there is a surface-matching lexical competitor

Native 'um's elicit prediction of low-frequency referents, but non-native 'um's do not

Speech comprehension involves extensive use of prediction. Linguistic prediction may be guided by the semantics or syntax, but also by the performance characteristics of the speech signal, such as disfluency. Previous studies have shown that listeners, when presented with the filler uh, exhibit a disfluency bias for discourse-new or unknown referents, drawing inferences about the source of the disfluency. The goal of the present study is to study the contrast between native and non-native disfluencies in speech comprehension. Experiment 1 presented listeners with pictures of high-frequency (e.g., a hand) and low-frequency objects (e.g., a sewing machine) and with fluent and disfluent instructions. Listeners were found to anticipate reference to low-frequency objects when encountering disfluency, thus attributing disfluency to speaker trouble in lexical retrieval. Experiment 2 showed that, when participants listened to disfluent non-native speech, no anticipation of low-frequency referents was observed. We conclude that listeners can adapt their predictive strategies to the (non-native) speaker at hand, extending our understanding of the role of speaker identity in speech comprehension

Джерельна база досліджень проблем німецького колоніалізму

Disfluencies (such as uh and uhm) are a common phenomenon in spontaneous speech. Rather than filtering these hesitations from the incoming speech signal, listeners are sensitive to disfluency and have been shown to actually use disfluencies for speech comprehension. For instance, disfluencies have been found to have beneficial effects on listeners’ memory. Accumulating evidence indicates that attentional mechanisms underlie this disfluency effect: upon encountering disfluency, listeners raise their attention to the incoming speech signal. The experiments reported here investigated whether these beneficial effects of disfluency also hold when listening to a non-native speaker. Recent studies on the perception of non-native disfluency suggest that disfluency effects on prediction are attenuated when listening to a non-native speaker. This attenuation may be a result of listeners being familiar with the frequent and more variant incidence of disfluencies in non-native speech. If listeners also modulate the beneficial effect of disfluency on memory when listening to a non-native speaker, it would indicate a certain amount of control on the part of the listener over how disfluencies affect attention, and thus comprehension. Furthermore, it would argue against the hypothesis that disfluencies affect comprehension in a rather automatic fashion (cf. the Temporal Delay Hypothesis). Using the Change Detection Paradigm, we presented participants with three-sentence passages that sometimes contained a filled pause (e.g., “... that the patient with the uh wound was...”). After each passage, participants saw a transcript of the spoken passage in which one word had been substituted (e.g., “wound” > “injury”). In our first experiment, participants were more accurate in recalling words from previously heard speech (i.e., detecting the change) if these words had been preceded by a disfluency (relative to a fluent passage). Our second experiment - using non-native speech materials - demonstrated that non-native uh’s elicited an effect of the same magnitude and in the same direction: when new participants listened to a non-native speaker producing the same passages, they were also more accurate on disfluent (as compared to fluent) trials. These data suggest that, upon encountering a disfluency, listeners raise their attention levels irrespective of the (non-)native identity of the speaker. Whereas listeners have been found to modulate prediction effects of disfluencies when listening to non-native speech, no such modulation was found for memory effects of disfluencies in the present data, thus potentially constraining the role of listener control in disfluency processing. The current study emphasizes the central role of attention in an account of disfluency processing