A study of semantic and syntactic processing in monolinguals and fluent early bilinguals

The present study consists of two reaction-time experiments administered in English. These experiments were designed to compare semantic and syntactic processing in English monolinguals and fluent early French-English bilinguals. Results of both experiments revealed that the bilinguals did not function as the English monolinguals did. That is, their reaction times were slower and they made twice as many errors in response to certain sentences. These findings are especially important for two reasons: (1) The bilinguals were all highly fluent, and in most cases dominant, in English, and (2) the bilinguals exhibited systematic differences in two different linguistic components (the semantic and the syntactic). The results are viewed as evidence of the interdependence of the bilinguals' languages. Some note is made of individual patterns of response, and two interpretations of linguistic interdependence are provided.     

The monolingual nature of speech segmentation by bilinguals.

Monolingual French speakers employ a syllable-based procedure in speech segmentation; monolingual English speakers use a stress-based segmentation procedure and do not use the syllable-based procedure. In the present study French-English bilinguals participated in segmentation experiments with English and French materials. Their results as a group did not simply mimic the performance of English monolinguals with English language materials and of French monolinguals with French language materials. Instead, the bilinguals formed two groups, defined by forced choice of a dominant language. Only the French-dominant groups showed syllabic segmentation and only with French language materials. The English-dominant group showed no syllabic segmentation in either language. However, the English-dominant group showed stress-based segmentation with English language materials; the French-dominant group did not. We argue that rhythmically based segmentation procedures are mutually exclusive, as a consequence of which speech segmentation by bilinguals is, in one respect at least, functionally monolingual.     

Left-hemisphere language lateralization in bilinguals: use of the concurrent activities paradigm

Previous visual and auditory lateralization studies have demonstrated that the languages of bilinguals are lateralized to the left hemisphere to the same extent as in monolingual controls (C. Soares & F. Grosjean, 1981, Perception and Psychophysics, 29, 599-604; C. Soares, 1982, Neuropsychologia, 20, 653-659). The present study tested the same group of Portuguese-English bilinguals and a group of English-speaking monolinguals on a series of concurrent activity, or time-sharing, tasks. Greater levels of disruption in finger tapping with the right hand than with the left hand occurred during the performance of those tasks which required overt speech production, and this for both bilinguals and monolinguals. As in the previous studies, there were no lateralization differences across the bilinguals' two languages or between bilinguals and monolinguals. Thus, further evidence for equal levels of left-hemisphere dominance for language in bilinguals and monolinguals was provided by the use of the concurrent activities paradigm.     

Cross-language activation in children's speech production: evidence from second language learners, bilinguals, and trilinguals

In five experiments, we examined cross-language activation during speech production in various groups of bilinguals and trilinguals who differed in nonnative language proficiency, language learning background, and age. In Experiments 1, 2, 3, and 5, German 5- to 8-year-old second language learners of English, German-English bilinguals, German-English-Language X trilinguals, and adult German-English bilinguals, respectively, named pictures in German and in English; in Experiment 4, 6- to 8-year-old German monolinguals named pictures in German. In both language conditions, cognate status was manipulated. We found that the bidirectional cognate facilitation effect was significant in all groups except the German monolinguals (Experiment 4) and, critically, the child second language learners (Experiment 1) in whom only native language (L1) German had an effect on second language (L2) English. The findings demonstrate how the integration of languages into a child's system follows a developmental path that, at lower levels of proficiency, allows only limited cross-language activation. The results are interpreted against the backdrop of the developing language systems of the children both for early second language learners and for early bi- and trilinguals.     

A disadvantage in bilingual sentence production modulated by syntactic frequency and similarity across languages

Bilingual speakers access individual words less fluently, quickly, and accurately than monolinguals, particularly when accessing low-frequency words. Here we examined whether the bilingual speech production disadvantage would (a) extend to full sentences above and beyond single word retrieval and whether it would be modulated by (b) structural frequency and (c) syntactic properties of the bilingual speakers’ other language. English monolinguals, Spanish–English bilinguals and Mandarin–English bilinguals were tested in a sentence production task conducted exclusively in English. Response times were modulated by bilingualism, structural frequency, and structural similarity across the bilingual speakers’ two languages. These results refine our knowledge regarding the scope of the bilingual disadvantage, demonstrate that frequency effects apply to syntactic structures, and also suggest that syntax is partially shared across bilinguals’ two languages.     

The perception of stop consonant voicing by Spanish-English bilinguals

The performance of Spanish-English bilinguals in two perception tasks, using a synthetic speech continuum varying in voice onset time, was compared with the performance of Spanish and English monolinguals. Voice onset time in speech production was also compared between these groups. Results in perception of bilinguals differed from that of both monolingual groups. Results of bilingual production in their two languages conformed with results obtained from each monolingual group. The perceptual results are interpreted in terms of differences in the use of available acoustic cues by bilingual and monolingual listeners of English and Spanish.     

Bilinguals’ twisted tongues: Frequency lag or interference?

Though bilinguals know many more words than monolinguals, within each language bilinguals exhibit some processing disadvantages, extending to sublexical processes specifying the sound structure of words (Gollan & Goldrick, Cognition, 125(3), 491–497, 2012). This study investigated the source of this bilingual disadvantage. Spanish–English bilinguals, Mandarin–English bilinguals, and English monolinguals repeated tongue twisters composed of English nonwords. Twister materials were made up of sound sequences that are unique to the English language (nonoverlapping) or sound sequences that are highly similar—yet phonetically distinct—in the two languages for the bilingual groups (overlapping). If bilingual disadvantages in tongue-twister production result from competition between phonetic representations in their two languages, bilinguals should have more difficulty selecting an intended target when similar sounds are activated in the overlapping sound sequences. Alternatively, if bilingual disadvantages reflect the relatively reduced frequency of use of sound sequences, bilinguals should have greater difficulty in the nonoverlapping condition (as the elements of such sound sequences are limited to a single language). Consistent with the frequency-lag account, but not the competition account, both Spanish–English and Mandarin–English bilinguals were disadvantaged in tongue-twister production only when producing twisters with nonoverlapping sound sequences. Thus, the bilingual disadvantage in tongue-twister production likely reflects reduced frequency of use of sound sequences specific to each language.     

The role of language familiarity in voice identification

Four experiments examined the effects of language characteristics on voice identification. In Experiment 1, monolingual English listeners identified bilinguals' voices much better when they spoke English than when they spoke German. The opposite outcome was found in Experiment 2, in which the listeners were monolingual in German. In Experiment 3, monolingual English listeners also showed better voice identification when bilinguals spoke a familiar language (English) than when they spoke an unfamiliar one (Spanish). However, English-Spanish bilinguals hearing the same voices showed a different pattern, with the English-Spanish difference being statistically eliminated. Finally, Experiment 4 demonstrated that, for English-dominant listeners, voice recognition deteriorates systematically as the passage being spoken is made less similar to English by rearranging words, rearranging syllables, and reversing normal text. Taken together, the four experiments confirm that language familiarity plays an important role in voice identification.     

What is a TOT? Cognate and translation effects on tip-of-the-tongue states in Spanish-English and tagalog-English bilinguals

The authors induced tip-of-the-tongue states (TOTs) for English words in monolinguals and bilinguals using picture stimuli with cognate (e.g., vampire, which is vampiro in Spanish) and noncognate (e.g., funnel, which is embudo in Spanish) names. Bilinguals had more TOTs than did monolinguals unless the target pictures had translatable cognate names, and bilinguals had fewer TOTs for noncognates they were later able to translate. TOT rates for the same targets in monolinguals indicated that these effects could not be attributed to target difficulty. Two popular TOT accounts must be modified to explain cognate and translatability facilitation effects, and cross-language interference cannot explain bilinguals' increased TOTs rates. Instead the authors propose that, relative to monolinguals, bilinguals are less able to activate representations specific to each language.     

The first steps in word learning are easier when the shoes fit: comparing monolingual and bilingual infants

English, French, and bilingual English-French 17-month-old infants were compared for their performance on a word learning task using the Switch task. Object names presented a /b/ vs. /g/ contrast that is phonemic in both English and French, and auditory strings comprised English and French pronunciations by an adult bilingual. Infants were habituated to two novel objects labeled 'bowce' or 'gowce' and were then presented with a switch trial where a familiar word and familiar object were paired in a novel combination, and a same trial with a familiar word–object pairing. Bilingual infants looked significantly longer to switch vs. same trials, but English and French monolinguals did not, suggesting that bilingual infants can learn word–object associations when the phonetic conditions favor their input. Monolingual infants likely failed because the bilingual mode of presentation increased phonetic variability and did not match their real-world input. Experiment 2 tested this hypothesis by presenting monolingual infants with nonce word tokens restricted to native language pronunciations. Monolinguals succeeded in this case. Experiment 3 revealed that the presence of unfamiliar pronunciations in Experiment 2, rather than a reduction in overall phonetic variability was the key factor to success, as French infants failed when tested with English pronunciations of the nonce words. Thus phonetic variability impacts how infants perform in the switch task in ways that contribute to differences in monolingual and bilingual performance. Moreover, both monolinguals and bilinguals are developing adaptive speech processing skills that are specific to the language(s) they are learning.     

Bimodal bilinguals co-activate both languages during spoken comprehension

Bilinguals have been shown to activate their two languages in parallel, and this process can often be attributed to overlap in input between the two languages. The present study examines whether two languages that do not overlap in input structure, and that have distinct phonological systems, such as American Sign Language (ASL) and English, are also activated in parallel. Hearing ASL-English bimodal bilinguals' and English monolinguals' eye-movements were recorded during a visual world paradigm, in which participants were instructed, in English, to select objects from a display. In critical trials, the target item appeared with a competing item that overlapped with the target in ASL phonology. Bimodal bilinguals looked more at competing item than at phonologically unrelated items and looked more at competing items relative to monolinguals, indicating activation of the sign-language during spoken English comprehension. The findings suggest that language co-activation is not modality specific, and provide insight into the mechanisms that may underlie cross-modal language co-activation in bimodal bilinguals, including the role that top-down and lateral connections between levels of processing may play in language comprehension.     

Bimodal bilinguals reveal the source of tip-of-the-tongue states

Bilinguals report more tip-of-the-tongue (TOT) failures than monolinguals. Three accounts of this disadvantage are that bilinguals experience between-language interference at (a) semantic and/or (b) phonological levels, or (c) that bilinguals use each language less frequently than monolinguals. Bilinguals who speak one language and sign another help decide between these alternatives because their languages lack phonological overlap. Twenty-two American Sign Language (ASL)-English bilinguals, 22 English monolinguals, and 11 Spanish-English bilinguals named 52 pictures in English. Despite no phonological overlap between languages, ASL-English bilinguals had more TOTs than monolinguals, and equivalent TOTs as Spanish-English bilinguals. These data eliminate phonological blocking as the exclusive source of bilingual disadvantages. A small advantage of ASL-English over Spanish-English bilinguals in correct retrievals is consistent with semantic interference and a minor role for phonological blocking. However, this account faces substantial challenges. We argue reduced frequency of use is the more comprehensive explanation of TOT rates in all bilinguals.     

Left hemisphere language lateralization in bilinguals and monolinguals

Tachistoscopic studies of lateralization in bilinguals suggest that there is a greater degree of right hemisphere involvement in their processing of language than is typically found in monolinguals. However, most of the studies reviewed failed to control the sex, handedness, and degree of fluency of the subjects and did not include a monolingual comparison group. The present study used adult right-handed males (Portuguese-English bilinguals and English-speaking monolinguals) in a tachistoscopic word-reading task. In Experiment 1, the words from the bilinguals’ two languages were presented in mixed blocks, while in Experiment 2, they were presented in separate blocks. The results were: (1) a similar level of left hemisphere advantage for language in the bilingual and the monolingual groups, (2) no evidence of greater heterogeneity of asymmetry patterns in bilinguals, and (3) a significant correlation (r=.61) for lateralization levels of the bilinguals’ two languages. These results indicate that language is processed primarily in the left hemisphere of both bilinguals and monolinguals.     

Bilingualism affects picture naming but not picture classification

Bilinguals named pictures in their dominant language more slowly (and with more errors) than did monolinguals. In contrast, bilinguals named the same pictures as quickly as did monolinguals on the fifth presentation (in Experiment 2) and classified them (as human made or natural) as quickly and accurately as did monolinguals (in Experiment 1). In addition, bilinguals retrieved English picture names more quickly if they knew the name in both Spanish and English (on the basis of a translation test that bilinguals completed after the timed tasks), and monolingual response times for the same materials suggested that this finding was not obtained simply because names that were easier to translate were easier in general. These findings suggest that bilinguals differ from monolinguals at a postconceptual processing level, that implicit activation of lexical representations in the nontarget language can facilitate retrieval in the target language, and that being bilingual is analogous to having a lexicon full of lower frequency words, relative to monolinguals.     

Language and Cognitive Predictors of Lexical Selection in Storytelling for Monolingual and Sequential Bilingual Children

The primary purpose of the present study was to test language and cognitive predictors of lexical selection in the storytelling of monolingual and bilingual children. Measures of language proficiency and cognitive ability were assessed with both English- and Mandarin-speaking monolinguals and Mandarin-English bilinguals aged 4 to 6 years old. To elicit stories, children watched a cartoon and told the story back. Bilinguals did these tasks in both of their languages. The results showed that the bilinguals told stories with as many different words as monolinguals of both languages but scored lower on measures of vocabulary. For monolinguals, vocabulary score was an important predictor of lexical variety even after controlling for age. For bilinguals, attentional control was a significant predictor of lexical variety in their second language, English. These results suggest that for monolingual children, vocabulary size is an important predictor of lexical variety in stories, while bilingual children might rely more on cognitive abilities to lexicalize concepts.     

Speech production units among bilinguals

This paper discusses processing units in speech production among bilinguals. First, naturally occurring intrasentential code-switching (switching languages within a sentence) was examined to show that bilinguals switch at syntactically definable constituent boundaries. Next, a code-switching elicitation experiment on Japanese/English bilinguals was conducted in which subjects were asked to speak about topics given and asked to switch to another language upon hearing randomly generated tones at 8–12 second intervals. The results suggest that bilinguals switch constituent-by-constituent and that this switching pattern is similar to monolinguals ' processing unit.I am grateful to Richard P. Meier and Felice Coles for comments and suggestions. Needless to say, all shortcomings are solely mine.     

Language experience influences audiovisual speech integration in unimodal and bimodal bilingual infants

Infants as young as 2 months can integrate audio and visual aspects of speech articulation. A shift of attention from the eyes towards the mouth of talking faces occurs around 6 months of age in monolingual infants. However, it is unknown whether this pattern of attention during audiovisual speech processing is influenced by speech and language experience in infancy. The present study investigated this question by analysing audiovisual speech processing in three groups of 4‐ to 8‐month‐old infants who differed in their language experience: monolinguals, unimodal bilinguals (infants exposed to two or more spoken languages) and bimodal bilinguals (hearing infants with Deaf mothers). Eye‐tracking was used to study patterns of face scanning while infants were viewing faces articulating syllables with congruent, incongruent and silent auditory tracks. Monolinguals and unimodal bilinguals increased their attention to the mouth of talking faces between 4 and 8 months, while bimodal bilinguals did not show any age difference in their scanning patterns. Moreover, older (6.6 to 8 months), but not younger, monolinguals (4 to 6.5 months) showed increased visual attention to the mouth of faces articulating audiovisually incongruent rather than congruent faces, indicating surprise or novelty. In contrast, no audiovisual congruency effect was found in unimodal or bimodal bilinguals. Results suggest that speech and language experience influences audiovisual integration in infancy. Specifically, reduced or more variable experience of audiovisual speech from the primary caregiver may lead to less sensitivity to the integration of audio and visual cues of speech articulation.     

Does bilingualism hamper lexical access in speech production?

In the present study, we tested the hypothesis that bilingualism may cause a linguistic disadvantage in lexical access even for bilinguals' first and dominant language. To this purpose, we conducted a picture naming experiment comparing the performance of monolinguals and highly-proficient, L1-dominant bilinguals. The results revealed that monolinguals name pictures faster than bilinguals, both when bilinguals perform picture naming in their first and dominant language and when they do so in their weaker second language. This is the first time it has been demonstrated that bilinguals show a naming disadvantage in their L1 in comparison to monolingual speakers.     

Dual language use in sign-speech bimodal bilinguals: fNIRS brain-imaging evidence

The brain basis of bilinguals’ ability to use two languages at the same time has been a hotly debated topic. On the one hand, behavioral research has suggested that bilingual dual language use involves complex and highly principled linguistic processes. On the other hand, brain-imaging research has revealed that bilingual language switching involves neural activations in brain areas dedicated to general executive functions not specific to language processing, such as general task maintenance. Here we address the involvement of language-specific versus cognitive-general brain mechanisms for bilingual language processing. We study a unique population, bimodal bilinguals proficient in signed and spoken languages, and we use an innovative brain-imaging technology, functional Near-Infrared Spectroscopy (fNIRS; Hitachi ETG-4000). Like fMRI, the fNIRS technology measures hemodynamic change, but it is also advanced in permitting movement for unconstrained speech and sign production. Participant groups included (i) hearing ASL–English bilinguals, (ii) ASL monolinguals, and (iii) English monolinguals. Imaging tasks included picture naming in “Monolingual mode” (using one language at a time) and in “Bilingual mode” (using both languages either simultaneously or in rapid alternation). Behavioral results revealed that accuracy was similar among groups and conditions. By contrast, neuroimaging results revealed that bilinguals in Bilingual mode showed greater signal intensity within posterior temporal regions (“Wernicke’s area”) than in Monolingual mode. Significance: Bilinguals’ ability to use two languages effortlessly and without confusion involves the use of language-specific posterior temporal brain regions. This research with both fNIRS and bimodal bilinguals sheds new light on the extent and variability of brain tissue that underlies language processing, and addresses the tantalizing questions of how language modality, sign and speech, impact language representation in the 7brain.     

Bilingual infants excel at foreign‐language talker recognition

Bilingual and monolingual infants differ in how they process linguistic aspects of the speech signal. But do they also differ in how they process non‐linguistic aspects of speech, such as who is talking? Here, we addressed this question by testing Canadian monolingual and bilingual 9‐month‐olds on their ability to learn to identify native Spanish‐speaking females in a face‐voice matching task. Importantly, neither group was familiar with Spanish prior to participating in the study. In line with our predictions, bilinguals succeeded in learning the face‐voice pairings, whereas monolinguals did not. We consider multiple explanations for this finding, including the possibility that simultaneous bilingualism enhances perceptual attentiveness to talker‐specific speech cues in infancy (even in unfamiliar languages), and that early bilingualism delays perceptual narrowing to language‐specific talker recognition cues. This work represents the first evidence that multilingualism in infancy affects the processing of non‐linguistic aspects of the speech signal, such as talker identity.