Pitch accents create dissociable syntactic and semantic expectations during sentence processing

Prosodic intonation modulates semantic incongruence: Evidence from an electrophysiological study

People always make semantic predictions based on preceding contexts which, however, can be beyond semantic information. This study examines the role of prosodic intonation as a non-semantic cue in semantic prediction. To compare effects of different intonation conditions on attenuating semantic incongruence between preceding contexts and target utterances, we recorded electroencephalogram when the participants listened to emotional utterances with congruent or incongruent endings and focused on two event-related potential components, N400 and P600, which relate to semantic and pragmatic processing, respectively. Interestingly, we observed that surprising intonation can mitigate the N400 in response to semantic incongruence, and this modulation was strongly correlated (r = 0.78) with the increase of P600 amplitude induced by the same intonation across individual participants. These findings consistently indicate the importance of prosodic intonation in promoting semantic prediction by lessening listeners' perceived semantic incongruence, broadening our understanding of how non-semantic cues affect human verbal communication.

Linear incrementality in focus and accentuation processing during sentence production: evidence from eye movements

Introduction

While considerable research in language production has focused on incremental processing during conceptual and grammatical encoding, prosodic encoding remains less investigated. This study examines whether focus and accentuation processing in speech production follows linear or hierarchical incrementality.

Methods

We employed visual world eye-tracking to investigate how focus and accentuation are processed during sentence production. Participants were asked to complete a scenario description task where they were prompted to use a predetermined sentence structure to accurately convey the scenario, thereby spontaneously accentuate the corresponding entity. We manipulated the positions of focus with accentuation (initial vs. medial) by changing the scenarios. The initial and medial positions correspond to the first and second nouns in sentences like "N1 is above N2, not N3."

Results

Our findings revealed that speech latencies were significantly shorter in the sentences with initial focus accentuation than those with medial focus accentuation. Furthermore, eye-tracking data demonstrated that speakers quickly displayed a preference for fixating on initial information after scenarios onset. Crucially, the time-course analysis revealed that the onset of the initial focus accentuation effect (around 460 ms) preceded that of the medial focus accentuation effect (around 920 ms).

Discussion

These results support that focus and accentuation processing during speech production prior to articulation follows linear incrementality rather than hierarchical incrementality.

Speech Prosody Serves Temporal Prediction of Language via Contextual Entrainment

Temporal prediction assists language comprehension. In a series of recent behavioral studies, we have shown that listeners specifically employ rhythmic modulations of prosody to estimate the duration of upcoming sentences, thereby speeding up comprehension. In the current human magnetoencephalography (MEG) study on participants of either sex, we show that the human brain achieves this function through a mechanism termed entrainment. Through entrainment, electrophysiological brain activity maintains and continues contextual rhythms beyond their offset. Our experiment combined exposure to repetitive prosodic contours with the subsequent presentation of visual sentences that either matched or mismatched the duration of the preceding contour. During exposure to prosodic contours, we observed MEG coherence with the contours, which was source-localized to right-hemispheric auditory areas. During the processing of the visual targets, activity at the frequency of the preceding contour was still detectable in the MEG; yet sources shifted to the (left) frontal cortex, in line with a functional inheritance of the rhythmic acoustic context for prediction. Strikingly, when the target sentence was shorter than expected from the preceding contour, an omission response appeared in the evoked potential record. We conclude that prosodic entrainment is a functional mechanism of temporal prediction in language comprehension. In general, acoustic rhythms appear to endow language for employing the brain's electrophysiological mechanisms of temporal prediction.

Sandhi-based predictability of pitch accent facilitates word recognition in Kansai Japanese speakers

This study investigates the predictability effects of pitch accent on word recognition using the sandhi rule in Kansai Japanese (KJ). Native KJ speakers and native Tokyo Japanese (TJ) speakers (control group) saw images of four objects while hearing modifier + noun phrases and selected the corresponding image as quickly as possible. The word-initial tone of the noun's initial mora was predictable or unpredictable based on the tone of the preceding modifier's final mora in KJ but not in TJ. Experiment 1 found faster reaction times in the predictable conditions compared with the unpredictable conditions in KJ speakers but only when the modifier had an all-low tone sequence. This finding suggests that a modifier-ending that changes following the sandhi rule can function as a reliable cue to constrain an upcoming tone, whereas a modifier-ending tone that remains the same as in the citation form cannot (although the next tone is predictable). Unexpectedly, we found the same effect, albeit weaker, in TJ speakers. Experiment 2 replicated this effect and additionally showed that the facilitation effect was not due to TJ speakers having sufficient exposure to KJ to be familiar with the KJ sandhi rule. We speculate that the effect in TJ speakers is related to a language universal constraint against a sequence of low tones without a high tone within a phonological word, which may urge listeners to listen for a high tone in the upcoming input.

Cleaning up the Brickyard: How Theory and Methodology Shape Experiments in Cognitive Neuroscience of Language

The capacity for language is a defining property of our species, yet despite decades of research, evidence on its neural basis is still mixed and a generalized consensus is difficult to achieve. We suggest that this is partly caused by researchers defining "language" in different ways, with focus on a wide range of phenomena, properties, and levels of investigation. Accordingly, there is very little agreement among cognitive neuroscientists of language on the operationalization of fundamental concepts to be investigated in neuroscientific experiments. Here, we review chains of derivation in the cognitive neuroscience of language, focusing on how the hypothesis under consideration is defined by a combination of theoretical and methodological assumptions. We first attempt to disentangle the complex relationship between linguistics, psychology, and neuroscience in the field. Next, we focus on how conclusions that can be drawn from any experiment are inherently constrained by auxiliary assumptions, both theoretical and methodological, on which the validity of conclusions drawn rests. These issues are discussed in the context of classical experimental manipulations as well as study designs that employ novel approaches such as naturalistic stimuli and computational modeling. We conclude by proposing that a highly interdisciplinary field such as the cognitive neuroscience of language requires researchers to form explicit statements concerning the theoretical definitions, methodological choices, and other constraining factors involved in their work.

Differential contributions of inferior frontal gyrus subregions to sentence processing guided by intonation

Auditory sentence comprehension involves processing content (semantics), grammar (syntax), and intonation (prosody). The left inferior frontal gyrus (IFG) is involved in sentence comprehension guided by these different cues, with neuroimaging studies preferentially locating syntactic and semantic processing in separate IFG subregions. However, this regional specialisation has not been confirmed with a neurostimulation method. Consequently, the causal role of such a specialisation remains unclear. This study probed the role of the posterior IFG (pIFG) for syntactic processing and the anterior IFG (aIFG) for semantic processing with repetitive transcranial magnetic stimulation (rTMS) in a task that required the interpretation of the sentence's prosodic realisation. Healthy participants performed a sentence completion task with syntactic and semantic decisions, while receiving 10 Hz rTMS over either left aIFG, pIFG, or vertex (control). Initial behavioural analyses showed an inhibitory effect on accuracy without task-specificity. However, electric field simulations revealed differential effects for both subregions. In the aIFG, stronger stimulation led to slower semantic processing, with no effect of pIFG stimulation. In contrast, we found a facilitatory effect on syntactic processing in both aIFG and pIFG, where higher stimulation strength was related to faster responses. Our results provide first evidence for the functional relevance of left aIFG in semantic processing guided by intonation. The stimulation effect on syntactic responses emphasises the importance of the IFG for syntax processing, without supporting the hypothesis of a pIFG-specific involvement. Together, the results support the notion of functionally specialised IFG subregions for diverse but fundamental cues for language processing.

Predicting syntactic structure

Prediction in language processing has been a topic of major interest in psycholinguistics for at least the last two decades, but most investigations focus on semantic rather than syntactic prediction. This review begins with a discussion of some influential models of parsing which assume that comprehenders have the ability to anticipate syntactic nodes, beginning with left-corner parsers and the garden-path model and ending with current information-theoretic approaches that emphasize online probabilistic prediction. We then turn to evidence for the prediction of specific syntactic forms, including coordinate clauses and noun phrases, verb arguments, and individual nouns, as well as studies that use morphosyntactic constraints to assess whether a specific semantic prediction has been made. The last section considers the implications of syntactic prediction for theories of language architecture and describes four avenues for future research.