Malte C. Viebahn

Tracking recognition of spoken words by tracking looks to printed words

Eye movements of Dutch participants were tracked as they looked at arrays of four words on a computer screen and followed spoken instructions (e.g., “Klik op het woord buffel”: Click on the word buffalo). The arrays included the target (e.g., buffel), a phonological competitor (e.g., buffer, buffer), and two unrelated distractors. Targets were monosyllabic or bisyllabic, and competitors mismatched targets only on either their onset or offset phoneme and only by one distinctive feature. Participants looked at competitors more than at distractors, but this effect was much stronger for offset-mismatch than onset-mismatch competitors. Fixations to competitors started to decrease as soon as phonetic evidence disfavouring those competitors could influence behaviour. These results confirm that listeners continuously update their interpretation of words as the evidence in the speech signal unfolds and hence establish the viability of the methodology of using eye movements to arrays of printed words to track spoken-word recognition.

Syntactic predictability in the recognition of carefully and casually produced speech

The present study investigated whether the recognition of spoken words is influenced by how predictable they are given their syntactic context and whether listeners assign more weight to syntactic predictability when acoustic-phonetic information is less reliable. Syntactic predictability was manipulated by varying the word order of past participles and auxiliary verbs in Dutch subordinate clauses. Acoustic-phonetic reliability was manipulated by presenting sentences either in a careful or a casual speaking style. In 3 eye-tracking experiments, participants recognized past participles more quickly when they occurred after their associated auxiliary verbs than when they preceded them. Response measures tapping into later stages of processing suggested that this effect was stronger for casually than for carefully produced sentences. These findings provide further evidence that syntactic predictability can influence word recognition and that this type of information is particularly useful for coping with acoustic-phonetic reductions in conversational speech. We conclude that listeners dynamically adapt to the different sources of linguistic information available to them.

Speaking style influences the brain’s electrophysiological response to grammatical errors in speech comprehension

This electrophysiological study asked whether the brain processes grammatical gender violations in casual speech differently than in careful speech. Native speakers of Dutch were presented with utterances that contained adjective–noun pairs in which the adjective was either correctly inflected with a word-final schwa (e.g., een spannende roman, “a suspenseful novel”) or incorrectly uninflected without that schwa (een spannend roman). Consistent with previous findings, the uninflected adjectives elicited an electrical brain response sensitive to syntactic violations when the talker was speaking in a careful manner. When the talker was speaking in a casual manner, this response was absent. A control condition showed electrophysiological responses for carefully as well as casually produced utterances with semantic anomalies, showing that listeners were able to understand the content of both types of utterance. The results suggest that listeners take information about the speaking style of a talker into account when processing the acoustic–phonetic information provided by the speech signal. Absent schwas in casual speech are effectively not grammatical gender violations. These changes in syntactic processing are evidence of contextually driven neural flexibility.