Phrase parsing in a second language as indexed by the closure positive shift: The impact of language experience and acoustic cue salience.

Despite the importance of prosodic processing in utterance parsing, a majority of studies investigating boundary localization in a second language focus on word segmentation. The goal of the present study was to investigate the parsing of phrase boundaries in first and second languages from different prosodic typologies (stress-timed vs. syllable-timed). Fifty English-French bilingual adults who varied in native language (French or English) and second language proficiency listened to English and French utterances with different prosodic structures while event-related brain potentials were recorded. The utterances were built around target words presented either in phrase-final position (bearing phrase-final lengthening) or in penultimate position. Each participant listened to both English and French stimuli, providing data in their native language (used as reference) and their second language. Target words in phrase-final position elicited closure positive shifts across listeners in both languages, regardless of the language-specific acoustic cues associated with phrase-final lengthening (shorter phrase-final lengthening in English compared to French). Interestingly, directional effects were observed, where learning to parse English as a second language in a native-like manner seemed to require a higher proficiency level than learning to parse French as a second language. This pattern of results supports the idea that L2 listeners need to learn to recognize L2-specific phrase-final lengthening regardless of the apparent similarity across languages and that some language combinations might present greater challenges than others.

Visual feedback of the tongue influences speech adaptation to a physical modification of the oral cavity.

Studies examining sensorimotor adaptation of speech to changing sensory conditions have demonstrated a central role for both auditory and somatosensory feedback in speech motor learning. The potential influence of visual feedback of oral articulators, which is not typically available during speech production but may nonetheless enhance oral motor control, remains poorly understood. The present study explores the influence of ultrasound visual feedback of the tongue on adaptation of speech production (focusing on the sound /s/) to a physical perturbation of the oral articulators (prosthesis altering the shape of the hard palate). Two visual feedback groups were tested that differed in the two-dimensional plane being imaged (coronal or sagittal) during practice producing /s/ words, along with a no-visual-feedback control group. Participants in the coronal condition were found to adapt their speech production across a broader range of acoustic spectral moments and syllable contexts than the no-feedback controls. In contrast, the sagittal group showed reduced adaptation compared to no-feedback controls. The results indicate that real-time visual feedback of the tongue is spontaneously integrated during speech motor adaptation, with effects that can enhance or interfere with oral motor learning depending on compatibility of the visual articulatory information with requirements of the speaking task.

Sensorimotor adaptation across the speech production workspace in response to a palatal perturbation.

Talkers have been shown to adapt the production of multiple vowel sounds simultaneously in response to altered auditory feedback. The present study extends this work by exploring the adaptation of speech production to a physical alteration of the vocal tract involving a palatal prosthesis that impacts both somatosensory and auditory feedback during the production of a range of consonants and vowels. Acoustic and kinematic measures of the tongue were used to examine the impact of the physical perturbation across the various speech sounds, and to assess learned changes following 20 min of speech practice involving the production of complex, variable sentences. As in prior studies, acoustic analyses showed perturbation and adaptation effects primarily for sounds directly involving interaction with the palate. Analyses of tongue kinematics, however, revealed systematic, robust effects of the perturbation and subsequent motor learning across the full range of speech sounds. The results indicate that speakers are able to reconfigure oral motor patterns during the production of multiple speech sounds spanning the articulatory workspace following a physical alteration of the vocal tract.

Adaptive and selective production of syllable duration and fundamental frequency as word segmentation cues by French-English bilinguals.

Despite the significant impact of prosody on L2 speakers' intelligibility, few studies have examined the production of prosodic cues associated with word segmentation in non-native or non-dominant languages. Here, 62 French-English bilingual adults, who varied in L1 (French or English) and language dominance, produced sentences built around syllable strings that can be produced either as one bisyllabic word or two monosyllabic words. Each participant produced both English and French utterances, providing both native productions (used as reference) and L2 productions. Acoustic analyses of the mean fundamental frequency (F0) and duration of both syllables of the ambiguous string revealed that speakers' relative language dominance affected the speakers' prosodic cue production over and above L1. Speakers also produced different prosodic patterns in English and French, suggesting that the production of prosodic cues associated with word-segmentation is both adaptive (modified by language experience) and selective (specific to each language).

Musical melody and speech intonation: singing a different tune.

Music and speech are often cited as characteristically human forms of communication. Both share the features of hierarchical structure, complex sound systems, and sensorimotor sequencing demands, and both are used to convey and influence emotions, among other functions [1]. Both music and speech also prominently use acoustical frequency modulations, perceived as variations in pitch, as part of their communicative repertoire. Given these similarities, and the fact that pitch perception and production involve the same peripheral transduction system (cochlea) and the same production mechanism (vocal tract), it might be natural to assume that pitch processing in speech and music would also depend on the same underlying cognitive and neural mechanisms. In this essay we argue that the processing of pitch information differs significantly for speech and music; specifically, we suggest that there are two pitch-related processing systems, one for more coarse-grained, approximate analysis and one for more fine-grained accurate representation, and that the latter is unique to music. More broadly, this dissociation offers clues about the interface between sensory and motor systems, and highlights the idea that multiple processing streams are a ubiquitous feature of neuro-cognitive architectures.

Misleading Bias-Driven Expectations in Referential Processing and the Facilitative Role of Contrastive Accent.

Probabilistic preferences are often facilitative in language processing and may assist in discourse prediction. However, occasionally these sources of information may lead to inaccurate expectations. The current study investigated a test case of this scenario. An eye-tracking experiment examined the interpretation of ambiguous personal pronouns in the context of implicit causality biases. We tested whether reference resolution may be facilitated online by contrastive accent in cases of a bias-inconsistent referent. Implicit causality biases directed looks to the biased noun phrase; however, when the name of the bias-inconsistent antecedent was accented (e.g., JOHN envied Bill because he ...), this tendency was modulated. Contrastive accent seems to dampen the occasionally confusing prediction of implicit causality biases in referential processing. This demonstrates one way in which the spoken language comprehension system copes with occasional misguidance of otherwise helpful probabilistic information.

Individual differences in the consistency of neural and behavioural responses to speech sounds.

There are documented individual differences among adults in the consistency of speech sound processing, both at neural and behavioural levels. Some adults show more consistent neural responses to speech sounds than others, as measured by an event-related potential called the frequency-following response (FFR); similarly, some adults show more consistent behavioural responses to native speech sounds than others, as measured by two-alternative forced choice (2AFC) and visual analog scaling (VAS) tasks. Adults also differ in how successfully they can perceive non-native speech sounds. Interestingly, it remains unclear whether these differences are related within individuals. In the current study, native English-speaking adults completed native phonetic perception tasks (2AFC and VAS), a non-native (German) phonetic perception task, and an FFR recording session. From these tasks, we derived measures of the consistency of participants' neural and behavioural responses to native speech as well as their non-native perception ability. We then examined the relationships among individual differences in these measures. Analysis of the behavioural measures revealed that more consistent responses to native sounds predicted more successful perception of unfamiliar German sounds. Analysis of neural and behavioural data did not reveal clear relationships between FFR consistency and our phonetic perception measures. This multimodal work furthers our understanding of individual differences in speech processing among adults, and may eventually lead to individualized approaches for enhancing non-native language acquisition in adulthood.

Exploring individual differences in native phonetic perception and their link to nonnative phonetic perception.

Adults differ considerably in their perception of both native and nonnative phonemes. For instance, when presented with continua of native phonemes on two-alternative forced choice (2AFC) or visual analog scaling (VAS) tasks, some people show sudden changes in responses (i.e., steep identification slopes) and others show gradual changes (i.e., shallow identification slopes). Moreover, some adults are more successful than others at learning unfamiliar phonemes. The predictors of these individual differences and the relationships between them are poorly understood. It also remains unclear to what extent different tasks (2AFC vs. VAS) may reflect distinct individual differences in perception. In two experiments, we addressed these questions by examining the relationships between individual differences in performance on native and nonnative phonetic perception tasks. We found that shallow 2AFC identification slopes were not related to shallow VAS identification slopes but were related to inconsistent VAS responses. Additionally, our results suggest that consistent native perception may play a role in promoting successful nonnative perception. These findings help characterize the nature of individual differences in phonetic perception and contribute to our understanding of how to measure such differences. This work also has implications for encouraging successful acquisition of new languages in adulthood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Acoustic and articulatory analysis of French vowels produced by congenitally blind adults and sighted adults.

In a previous paper [Ménard et al., J. Acoust. Soc. Am. 126, 1406-1414 (2009)], it was demonstrated that, despite enhanced auditory discrimination abilities for synthesized vowels, blind adult French speakers produced vowels that were closer together in the acoustic space than those produced by sighted adult French speakers, suggesting finer control of speech production in the sighted speakers. The goal of the present study is to further investigate the articulatory effects of visual deprivation on vowels produced by 11 blind and 11 sighted adult French speakers. Synchronous ultrasound, acoustic, and video recordings of the participants articulating the ten French oral vowels were made. Results show that sighted speakers produce vowels that are spaced significantly farther apart in the acoustic vowel space than blind speakers. Furthermore, blind speakers use smaller differences in lip protrusion but larger differences in tongue position and shape than their sighted peers to produce rounding and place of articulation contrasts. Trade-offs between lip and tongue positions were examined. Results are discussed in the light of the perception-for-action control theory.

Early auditory responses to speech sounds in Parkinson's disease: preliminary data.

Parkinson's disease (PD), as a manifestation of basal ganglia dysfunction, is associated with a number of speech deficits, including reduced voice modulation and vocal output. Interestingly, previous work has shown that participants with PD show an increased feedback-driven motor response to unexpected fundamental frequency perturbations during speech production, and a heightened ability to detect differences in vocal pitch relative to control participants. Here, we explored one possible contributor to these enhanced responses. We recorded the frequency-following auditory brainstem response (FFR) to repetitions of the speech syllable [da] in PD and control participants. Participants with PD displayed a larger amplitude FFR related to the fundamental frequency of speech stimuli relative to the control group. The current preliminary results suggest the dysfunction of the basal ganglia in PD contributes to the early stage of auditory processing and may reflect one component of a broader sensorimotor processing impairment associated with the disease.

Age of Acquisition Modulates Alpha Power During Bilingual Speech Comprehension in Noise.

Research on bilingualism has grown exponentially in recent years. However, the comprehension of speech in noise, given the ubiquity of both bilingualism and noisy environments, has seen only limited focus. Electroencephalogram (EEG) studies in monolinguals show an increase in alpha power when listening to speech in noise, which, in the theoretical context where alpha power indexes attentional control, is thought to reflect an increase in attentional demands. In the current study, English/French bilinguals with similar second language (L2) proficiency and who varied in terms of age of L2 acquisition (AoA) from 0 (simultaneous bilinguals) to 15 years completed a speech perception in noise task. Participants were required to identify the final word of high and low semantically constrained auditory sentences such as "Stir your coffee with a spoon" vs. "Bob could have known about the spoon" in both of their languages and in both noise (multi-talker babble) and quiet during electrophysiological recording. We examined the effects of language, AoA, semantic constraint, and listening condition on participants' induced alpha power during speech comprehension. Our results show an increase in alpha power when participants were listening in their L2, suggesting that listening in an L2 requires additional attentional control compared to the first language, particularly early in processing during word identification. Additionally, despite similar proficiency across participants, our results suggest that under difficult processing demands, AoA modulates the amount of attention required to process the second language.

Effects of cooperating and conflicting prosody in spoken English garden path sentences: ERP evidence for the boundary deletion hypothesis.

In reading, a comma in the wrong place can cause more severe misunderstandings than the lack of a required comma. Here, we used ERPs to demonstrate that a similar effect holds for prosodic boundaries in spoken language. Participants judged the acceptability of temporarily ambiguous English "garden path" sentences whose prosodic boundaries were either in line or in conflict with the actual syntactic structure. Sentences with incongruent boundaries were accepted less than those with missing boundaries and elicited a stronger on-line brain response in ERPs (N400/P600 components). Our results support the notion that mentally deleting an overt prosodic boundary is more costly than postulating a new one and extend previous findings, suggesting an immediate role of prosody in sentence comprehension. Importantly, our study also provides new details on the profile and temporal dynamics of the closure positive shift (CPS), an ERP component assumed to reflect prosodic phrasing in speech and music in real time. We show that the CPS is reliably elicited at the onset of prosodic boundaries in English sentences and is preceded by negative components. Its early onset distinguishes the speech CPS in adults both from prosodic ERP correlates in infants and from the "music CPS" previously reported for trained musicians.

Sensorimotor integration for speech motor learning involves the inferior parietal cortex.

Sensorimotor integration is important for motor learning. The inferior parietal lobe, through its connections with the frontal lobe and cerebellum, has been associated with multisensory integration and sensorimotor adaptation for motor behaviors other than speech. In the present study, the contribution of the inferior parietal cortex to speech motor learning was evaluated using repetitive transcranial magnetic stimulation (rTMS) prior to a speech motor adaptation task. Subjects' auditory feedback was altered in a manner consistent with the auditory consequences of an unintended change in tongue position during speech production, and adaptation performance was used to evaluate sensorimotor plasticity and short-term learning. Prior to the feedback alteration, rTMS or sham stimulation was applied over the left supramarginal gyrus (SMG). Subjects who underwent the sham stimulation exhibited a robust adaptive response to the feedback alteration whereas subjects who underwent rTMS exhibited a diminished adaptive response. The results suggest that the inferior parietal region, in and around SMG, plays a role in sensorimotor adaptation for speech. The interconnections of the inferior parietal cortex with inferior frontal cortex, cerebellum and primary sensory areas suggest that this region may be an important component in learning and adapting sensorimotor patterns for speech.

Articulatory and acoustic adaptation to palatal perturbation.

Previous work has established that speakers have difficulty making rapid compensatory adjustments in consonant production (especially in fricatives) for structural perturbations of the vocal tract induced by artificial palates with thicker-than-normal alveolar regions. The present study used electromagnetic articulography and simultaneous acoustic recordings to estimate tongue configurations during production of [s s t k] in the presence of a thin and a thick palate, before and after a practice period. Ten native speakers of English participated in the study. In keeping with previous acoustic studies, fricatives were more affected by the palate than were the stops. The thick palate lowered the center of gravity and the jaw was lower and the tongue moved further backwards and downwards. Center of gravity measures revealed complete adaptation after training, and with practice, subjects' decreased interlabial distance. The fact that adaptation effects were found for [k], which are produced with an articulatory gesture not directly impeded by the palatal perturbation, suggests a more global sensorimotor recalibration that extends beyond the specific articulatory target.

Bilingual language experience and the neural underpinnings of working memory.

A longstanding question in cognitive neuroscience and in the bilingualism literature is how early language experience influences brain development and cognitive outcomes, and whether these effects are global or specific to language-related processes. The current investigation examined the effect of the timing of language learning on the performance and neural correlates of phonological and non-verbal working memory, subcomponents of executive function. Three groups of bilinguals, who varied in terms of the timing of second language learning (i.e., simultaneous bilinguals learned their two languages from birth; early and late bilinguals who learned their second language before or after 5 years of age, respectively), performed phonological and non-verbal working memory tasks in the magnetic resonance imaging scanner. Results showed that there were no group differences in performance on either of the tasks, or in the neural correlates of performance of the non-verbal task. However, critically, we showed that despite similar behavioural performance, the groups differed in the patterns of neural recruitment during performance of the phonological working memory task. The pattern of group differences was non-linear, demonstrating similar neural recruitment for simultaneous and late bilinguals that differed from early bilinguals. Findings from the current study suggest a dynamic mapping between the brain and cognition, contributing to our current understanding of the effect of the timing of language learning on cognitive processes and demonstrating a specific effect on language-related executive function.

Near native-like stress pattern perception in English-French bilinguals as indexed by the mismatch negativity.

We examined lexical stress processing in English-French bilinguals. Auditory mismatch negativity (MMN) responses were recorded in response to English and French pseudowords, whose primary stress occurred either on a language-consistent "usual" or language-inconsistent "unusual" syllable. In most conditions, the pseudowords elicited two consecutive MMNs, and somewhat surprisingly, these MMNs were not systematically modulated by bilingual experience. This suggests that it is possible to achieve native-like pre-attentive processing of lexical stress, even in a language that one has not learned since birth.

Spoken Word Segmentation in First and Second Language: When ERP and Behavioral Measures Diverge.

Previous studies of word segmentation in a second language have yielded equivocal results. This is not surprising given the differences in the bilingual experience and proficiency of the participants and the varied experimental designs that have been used. The present study tried to account for a number of relevant variables to determine if bilingual listeners are able to use native-like word segmentation strategies. Here, 61 French-English bilingual adults who varied in L1 (French or English) and language dominance took part in an audiovisual integration task while event-related brain potentials (ERPs) were recorded. Participants listened to sentences built around ambiguous syllable strings (which could be disambiguated based on different word segmentation patterns), during which an illustration was presented on screen. Participants were asked to determine if the illustration was related to the heard utterance or not. Each participant listened to both English and French utterances, providing segmentation patterns that included both their native language (used as reference) and their L2. Interestingly, different patterns of results were observed in the event-related potentials (online) and behavioral (offline) results, suggesting that L2 participants showed signs of being able to adapt their segmentation strategies to the specifics of the L2 (online ERP results), but that the extent of the adaptation varied as a function of listeners' language experience (offline behavioral results).

Earlier age of second language learning induces more robust speech encoding in the auditory brainstem in adults, independent of amount of language exposure during early childhood.

Learning a second language (L2) at a young age is a driving factor of functional neuroplasticity in the auditory brainstem. To date, it remains unclear whether these effects remain stable until adulthood and to what degree the amount of exposure to the L2 in early childhood might affect their outcome. We compared three groups of adult English-French bilinguals in their ability to categorize English vowels in relation to their frequency following responses (FFR) evoked by the same vowels. At the time of testing, cognitive abilities as well as fluency in both languages were matched between the (1) simultaneous bilinguals (SIM, N = 18); (2) sequential bilinguals with L1-English (N = 14); and (3) sequential bilinguals with L1-French (N = 11). Our results show that the L1-English group show sharper category boundaries in identification of the vowels compared to the L1-French group. Furthermore, the same pattern was reflected in the FFRs (i.e., larger FFR responses in L1-English > SIM > L1-French), while again only the difference between the L1-English and the L1-French group was statistically significant; nonetheless, there was a trend towards larger FFR in SIM compared to L1-French. Our data extends previous literature showing that exposure to a language during the first years of life induces functional neuroplasticity in the auditory brainstem that remains stable until at least young adulthood. Furthermore, the findings suggest that amount of exposure (i.e., 100% vs. 50%) to that language does not differentially shape the robustness of the perceptual abilities or the auditory brainstem encoding of phonetic categories of the language. Statement of significance: Previous studies have indicated that early age of L2 acquisition induces functional neuroplasticity in the auditory brainstem during processing of the L2. This study compared three groups of adult bilinguals who differed in their age of L2 acquisition as well as the amount of exposure to the L2 during early childhood. We demonstrate for the first time that the neuroplastic effect in the brainstem remains stable until young adulthood and that the amount of L2 exposure does not influence behavioral or brainstem plasticity. Our study provides novel insights into low-level auditory plasticity as a function of varying bilingual experience.

Production and perception of French vowels by congenitally blind adults and sighted adults.

The goal of this study is to investigate the production and perception of French vowels by blind and sighted speakers. 12 blind adults and 12 sighted adults served as subjects. The auditory-perceptual abilities of each subject were evaluated by discrimination tests (AXB). At the production level, ten repetitions of the ten French oral vowels were recorded. Formant values and fundamental frequency values were extracted from the acoustic signal. Measures of contrasts between vowel categories were computed and compared for each feature (height, place of articulation, roundedness) and group (blind, sighted). The results reveal a significant effect of group (blind vs sighted) on production, with sighted speakers producing vowels that are spaced further apart in the vowel space than those of blind speakers. A group effect emerged for a subset of the perceptual contrasts examined, with blind speakers having higher peak discrimination scores than sighted speakers. Results suggest an important role of visual input in determining speech goals.

Perceptual recalibration of speech sounds following speech motor learning.

The functional sensorimotor nature of speech production has been demonstrated in studies examining speech adaptation to auditory and/or somatosensory feedback manipulations. These studies have focused primarily on flexible motor processes to explain their findings, without considering modifications to sensory representations resulting from the adaptation process. The present study explores whether the perceptual representation of the /s-/ contrast may be adjusted following the alteration of auditory feedback during the production of /s/-initial words. Consistent with prior studies of speech adaptation, talkers exposed to the feedback manipulation were found to adapt their motor plans for /s/-production in order to compensate for the effects of the sensory perturbation. In addition, a shift in the /s-/ category boundary was observed that reduced the functional impact of the auditory feedback manipulation by increasing the perceptual "distance" between the category boundary and subjects' altered /s/-stimuli-a pattern of perceptual adaptation that was not observed in two separate control groups. These results suggest that speech adaptation to altered auditory feedback is not limited to the motor domain, but rather involves changes in both motor output and auditory representations of speech sounds that together act to reduce the impact of the perturbation.