Sonja Rossi

The Impact of Proficiency on Syntactic Second-language Processing of German and Italian: Evidence from Event-related Potentials

The present study investigated the role of proficiency in late second-language (L2) processing using comparable stimuli in German and Italian. Both sets of stimuli consisted of simple active sentences including a word category violation, a morphosyntactic agreement violation, or a combination of the two. Four experiments were conducted to study high- and low-proficiency L2 learners of German as well as high- and low-proficiency L2 learners of Italian. High-proficiency L2 learners in both languages showed the same event-related potential (ERP) components as native speakers for all syntactic violations. For the word category violation, they displayed an early anterior negativity (ELAN), an additional negativity reflecting reference-related processes, and a late P600 evidencing processes of reanalysis. For the processing of the morphosyntactic error, an anterior negativity (LAN) and a P600 were observed, whereas for the combined violation, the same ERP components were found as in the pure category violation. In high-proficiency L2 learners, the timing of the processing steps was equivalent to that of native speakers, although some amplitude differences were present. Low-proficiency L2 learners, however, showed qualitative differences in the agreement violation characterized by the absence of the LAN and quantitative differences reflected in a delayed P600 in every violation condition. These findings emphasize that with a high proficiency, late L2 learners can indeed show native-like neural responses with the timing approximating that of native speakers. This challenges the idea that there are fundamental differences in language processing in the brain between natives and late L2 learners.

Sensitivity of Newborn Auditory Cortex to the Temporal Structure of Sounds

Understanding the rapidly developing building blocks of speech perception in infancy requires a close look at the auditory prerequisites for speech sound processing. Pioneering studies have demonstrated that hemispheric specializations for language processing are already present in early infancy. However, whether these computational asymmetries can be considered a function of linguistic attributes or a consequence of basic temporal signal properties is under debate. Several studies in adults link hemispheric specialization for certain aspects of speech perception to an asymmetry in cortical tuning and reveal that the auditory cortices are differentially sensitive to spectrotemporal features of speech. Applying concurrent electrophysiological (EEG) and hemodynamic (near-infrared spectroscopy) recording to newborn infants listening to temporally structured nonspeech signals, we provide evidence that newborns process nonlinguistic acoustic stimuli that share critical temporal features with language in a differential manner. The newborn brain preferentially processes temporal modulations especially relevant for phoneme perception. In line with multi-time-resolution conceptions, modulations on the time scale of phonemes elicit strong bilateral cortical responses. Our data furthermore suggest that responses to slow acoustic modulations are lateralized to the right hemisphere. That is, the newborn auditory cortex is sensitive to the temporal structure of the auditory input and shows an emerging tendency for functional asymmetry. Hence, our findings support the hypothesis that development of speech perception is linked to basic capacities in auditory processing. From birth, the brain is tuned to critical temporal properties of linguistic signals to facilitate one of the major needs of humans: to communicate.

When word category information encounters morphosyntax: An ERP study

The present study investigated the relationship between two different syntactic information types, namely word category and morphosyntax. The event-related brain potential (ERP) pattern of acoustically presented sentences containing two syntactic anomalies (word category and subject-verb agreement) was compared to the ERP response to sentences containing a single violation. The ERPs for the agreement violation revealed a left anterior negativity (LAN) indicating the detection of the morphosyntactic error, followed by a P600 reflecting processes of reanalysis. The ERPs for both the category and the combined violation showed an early negativity reflecting processes of phrase structure building, followed by a P600 indicating syntactic reanalysis. Additionally, a broadly distributed negativity following the early negativity and preceding the P600 was observed. This ERP component is suggested to reflect reference specification processes arising from the specific sentence structure used in the present study. The ERP pattern for the combined violation suggests no additivity or interaction between the two syntactic anomalies in the early time windows (early negativity, reference-related negativity, and LAN), whereas interactive effects are observed in a late time range (P600).

Acoustic Processing of Temporally Modulated Sounds in Infants: Evidence from a Combined Near-Infrared Spectroscopy and EEG Study

Speech perception requires rapid extraction of the linguistic content from the acoustic signal. The ability to efficiently process rapid changes in auditory information is important for decoding speech and thereby crucial during language acquisition. Investigating functional networks of speech perception in infancy might elucidate neuronal ensembles supporting perceptual abilities that gate language acquisition. Interhemispheric specializations for language have been demonstrated in infants. How these asymmetries are shaped by basic temporal acoustic properties is under debate. We recently provided evidence that newborns process non-linguistic sounds sharing temporal features with language in a differential and lateralized fashion. The present study used the same material while measuring brain responses of 6 and 3 month old infants using simultaneous recordings of electroencephalography (EEG) and near-infrared spectroscopy (NIRS). NIRS reveals that the lateralization observed in newborns remains constant over the first months of life. While fast acoustic modulations elicit bilateral neuronal activations, slow modulations lead to right-lateralized responses. Additionally, auditory-evoked potentials and oscillatory EEG responses show differential responses for fast and slow modulations indicating a sensitivity for temporal acoustic variations. Oscillatory responses reveal an effect of development, that is, 6 but not 3 month old infants show stronger theta-band desynchronization for slowly modulated sounds. Whether this developmental effect is due to increasing fine-grained perception for spectrotemporal sounds in general remains speculative. Our findings support the notion that a more general specialization for acoustic properties can be considered the basis for lateralization of speech perception. The results show that concurrent assessment of vascular based imaging and electrophysiological responses have great potential in the research on language acquisition.

From Acoustic Segmentation to Language Processing: Evidence from Optical Imaging

During language acquisition in infancy and when learning a foreign language, the segmentation of the auditory stream into words and phrases is a complex process. Intuitively, learners use “anchors” to segment the acoustic speech stream into meaningful units like words and phrases. Regularities on a segmental (e.g., phonological) or suprasegmental (e.g., prosodic) level can provide such anchors. Regarding the neuronal processing of these two kinds of linguistic cues a left-hemispheric dominance for segmental and a right-hemispheric bias for suprasegmental information has been reported in adults. Though lateralization is common in a number of higher cognitive functions, its prominence in language may also be a key to understanding the rapid emergence of the language network in infants and the ease at which we master our language in adulthood. One question here is whether the hemispheric lateralization is driven by linguistic input per se or whether non-linguistic, especially acoustic factors, “guide” the lateralization process. Methodologically, functional magnetic resonance imaging provides unsurpassed anatomical detail for such an enquiry. However, instrumental noise, experimental constraints and interference with EEG assessment limit its applicability, pointedly in infants and also when investigating the link between auditory and linguistic processing. Optical methods have the potential to fill this gap. Here we review a number of recent studies using optical imaging to investigate hemispheric differences during segmentation and basic auditory feature analysis in language development.

Shedding Light on Words and Sentences: Near-Infrared Spectroscopy in Language Research.

Investigating the neuronal network underlying language processing may contribute to a better understanding of how the brain masters this complex cognitive function with surprising ease and how language is acquired at a fast pace in infancy. Modern neuroimaging methods permit to visualize the evolvement and the function of the language network. The present paper focuses on a specific methodology, functional near-infrared spectroscopy (fNIRS), providing an overview over studies on auditory language processing and acquisition. The methodology detects oxygenation changes elicited by functional activation of the cerebral cortex. The main advantages for research on auditory language processing and its development during infancy are an undemanding application, the lack of instrumental noise, and its potential to simultaneously register electrophysiological responses. Also it constitutes an innovative approach for studying developmental issues in infants and children. The review will focus on studies on word and sentence processing including research in infants and adults.

Developmental changes in brain activation and functional connectivity during response inhibition in the early childhood brain

Response inhibition is an attention function which develops relatively early during childhood. Behavioral data suggest that by the age of 3, children master the basic task requirements for the assessment of response inhibition but performance improves substantially until the age of 7. The neuronal mechanisms underlying these developmental processes, however, are not well understood. In this study, we examined brain activation patterns and behavioral performance of children aged between 4 and 6 years compared to adults by applying a go/no-go paradigm during near-infrared spectroscopy (NIRS) brain imaging. We furthermore applied task-independent functional connectivity measures to the imaging data to identify maturation of intrinsic neural functional networks. We found a significant group×condition related interaction in terms of inhibition-related reduced right fronto-parietal activation in children compared to adults. In contrast, motor-related activation did not differ between age groups. Functional connectivity analysis revealed that in the childrens group, short-range coherence within frontal areas was stronger, and long-range coherence between frontal and parietal areas was weaker, compared to adults. Our findings show that in children aged from 4 to 6 years fronto-parietal brain maturation plays a crucial part in the cognitive development of response inhibition.

Electrophysiological evidence for domain-general inhibitory control during bilingual language switching.

This paper presents an experiment that explored the role of domain–general inhibitory control on language switching. Reaction times (RTs) and event–related brain potentials (ERPs) were recorded when low–proficient bilinguals with high and low inhibitory control (IC) switched between overt picture naming in both their L1 and L2. Results showed that the language switch costs of bilinguals with high–IC were symmetrical, while that of bilinguals with low–IC were not. The N2 component failed to show a significant interaction between group, language and task, indicating that inhibition may not comes into play during the language task schema competition phase. The late positive component (LPC), however, showed larger amplitudes for L2 repeat and switch trials than for L1 trials in the high–IC group, indicating that inhibition may play a key role during the lexical response selection phase. These findings suggest that domain–general inhibitory control plays an important role in modulating language switch costs and its influence can be specified in lexical selection phase.

The effect of cognitive flexibility on task switching and language switching

Aims: The present study aimed at investigating whether cognitive flexibility plays the same role in language switching as in task switching. Design: Cognitive flexibility (CF) of 52 low proficiency Chinese (L1)–English (L2) bilinguals was assessed by the Wisconsin Card Sorting Task. These bilinguals were then subdivided in 26 high- and 26 low-CF participants. Both groups performed a task-switching (Simon switch task) and a language-switching task (picture-naming task). The former task required participants to press a button congruent or incongruent to the pointing direction of an arrow, while in the latter participants had to name pictures in their L1 and L2. Data and analysis: Both response latencies and accuracy scores were obtained. Afterwards switch costs (i.e. longer latencies or reduced accuracy for switch in contrast to repeat trials) were calculated. Findings: Results of the Simon switch task showed that switch costs for congruent and incongruent trials were symmetrical in the high-CF group, whereas the low-CF group showed larger switch costs for congruent than incongruent trials. Similarly, results of the language-switch task showed symmetrical switch costs for naming pictures in their L1 and L2 for the high-CF group, but L1 switch costs were larger than L2 ones in the low-CF group. These findings indicate that cognitive flexibility can modulate switch costs of two different switching tasks. This is in line with the inhibitory control model and the task-set inertia theory which assume that cognitive flexibility might modulate the symmetry of different types of switch costs via inhibition. This study provides first direct evidence that cognitive flexibility plays a comparably important role in language switching as well as in task switching. Thus, cognitive flexibility can be beneficial for low proficiency bilinguals’ inhibitory control during task switching and language switching.

Effects of working memory capacity in processing wh‐extractions: eye‐movement evidence from Chinese–English bilinguals

By using the eye-tracking method, the present study explores whether working memory capacity assessed via the second language (L2) reading span (L2WMC) as well as the operational span task (OSPAN) affects the processing of subject-extraction and object-extraction in Chinese–English bilinguals. Results showed that L2WMC has no effects on the grammatical judgement accuracies, the first fixation duration, gaze duration, go-past times and total fixation duration of the critical regions in wh-extractions. In contrast, OSPAN influences the first fixation duration and go-past times of the critical regions in wh-extractions. Specifically, in region 1, (e.g., Who do you think loved the comedian [region 1] with [region 2] all his heart [subject-extraction]? versus Who do you think the comedian loved [region 1] with [region 2] all his heart? [object-extraction]), participants with high OSPAN were much slower than those with low OSPAN in their first fixation duration in reading subject-extractions, whereas there were no differences between participants with different OSPANs in reading object-extractions. In region 2, participants with high OSPAN were much faster than those with low OSPAN in their go-past times of object-extractions. These results indicated that individual differences in OSPAN rather than in L2WMC more strongly affect processing of wh-extractions. Thus, OSPAN results to be more suitable to explore the influences of working memory while processing L2 sentences with complex syntax, at least for intermediate proficient bilinguals. Results of the study also provide further support for the Capacity Theory of Comprehension.