Brain bases of English morphological processing: A comparison between Chinese-English,Spanish-English bilingual,and English monolingual children

How do early bilingual experiences influence children's neural architecture for word processing? Dual language acquisition can yield common influences that may be shared across different bilingual groups, as well as language-specific influences stemming from a given language pairing. To investigate these effects, we examined bilingual English speakers of Chinese or Spanish, and English monolinguals, all raised in the US (N = 152, ages 5–10). Children completed an English morphological word processing task during fNIRS neuroimaging. The findings revealed both language-specific and shared bilingual effects. The language-specific effects were that Chinese and Spanish bilinguals showed principled differences in their neural organization for English lexical morphology. The common bilingual effects shared by the two groups were that in both bilingual groups, increased home language proficiency was associated with stronger left superior temporal gyrus (STG) activation when processing the English word structures that are most dissimilar from the home language. The findings inform theories of language and brain development during the key periods of neural reorganization for learning to read by illuminating experience-based plasticity in linguistically diverse learners.     

Does code-switching influence novel word learning?

Code-switching occurs regularly in the input to bilingual children. Yet, the effect of code-switched input on language development is unclear. To test whether word learning would be affected by code-switching, Spanish–English bilingual children (N = 45, 19 boys, Mean_Age = 5.05 years; ethnicity: 37 Hispanic/Latino, six Non-Hispanic/Latino, two unreported) were taught English-like novel words in two conditions. In the English-only condition, definitions for novel words were provided entirely in English. In the code-switch condition, definitions for novel words were provided in English and Spanish, incorporating code-switches. Children required fewer exposures to retain novel words in the code-switch than the English-only condition and this effect was not moderated by children's language ability or exposure to code-switching, suggesting that code-switched input does not pose word-learning risks to bilingual children, including children with lower levels of language ability.     

Transfer effects from language processing to visual attention dynamics: The impact of orthographic transparency

The consistency between letters and sounds varies across languages. These differences have been proposed to be associated with different reading mechanisms (lexical vs. phonological), processing grain sizes (coarse vs. fine) and attentional windows (whole words vs. individual letters). This study aimed to extend this idea to writing to dictation. For that purpose, we evaluated whether the use of different types of processing has a differential impact on local windowing attention: phonological (local) processing in a transparent language (Spanish) and lexical (global) processing of an opaque language (English). Spanish and English monolinguals (Experiment 1) and Spanish–English bilinguals (Experiment 2) performed a writing to dictation task followed by a global–local task. The first key performance showed a critical dissociation between languages: the response times (RTs) from the Spanish writing to dictation task was modulated by word length, whereas the RTs from the English writing to dictation task was modulated by word frequency and age of acquisition, as evidence that language transparency biases processing towards phonological or lexical strategies. In addition, after a Spanish task, participants more efficiently processed local information, which resulted in both the benefit of global congruent information and the reduced cost of incongruent global information. Additionally, the results showed that bilinguals adapt their attentional processing depending on the orthographic transparency.     

Bridging ears and eyes when learning spoken words: On the effects of bilingual experience at 30 months

From the very first moments of their lives, infants selectively attend to the visible orofacial movements of their social partners and apply their exquisite speech perception skills to the service of lexical learning. Here we explore how early bilingual experience modulates children's ability to use visible speech as they form new lexical representations. Using a cross‐modal word‐learning task, bilingual children aged 30 months were tested on their ability to learn new lexical mappings in either the auditory or the visual modality. Lexical recognition was assessed either in the same modality as the one used at learning (‘same modality’ condition: auditory test after auditory learning, visual test after visual learning) or in the other modality (‘cross‐modality’ condition: visual test after auditory learning, auditory test after visual learning). The results revealed that like their monolingual peers, bilingual children successfully learn new words in either the auditory or the visual modality and show cross‐modal recognition of words following auditory learning. Interestingly, as opposed to monolinguals, they also demonstrate cross‐modal recognition of words upon visual learning. Collectively, these findings indicate a bilingual edge in visual word learning, expressed in the capacity to form a recoverable cross‐modal representation of visually learned words.     

Statistical learning of multiple speech streams: A challenge for monolingual infants

Language acquisition depends on the ability to detect and track the distributional properties of speech. Successful acquisition also necessitates detecting changes in those properties, which can occur when the learner encounters different speakers, topics, dialects, or languages. When encountering multiple speech streams with different underlying statistics but overlapping features, how do infants keep track of the properties of each speech stream separately? In four experiments, we tested whether 8‐month‐old monolingual infants (N = 144) can track the underlying statistics of two artificial speech streams that share a portion of their syllables. We first presented each stream individually. We then presented the two speech streams in sequence, without contextual cues signaling the different speech streams, and subsequently added pitch and accent cues to help learners track each stream separately. The results reveal that monolingual infants experience difficulty tracking the statistical regularities in two speech streams presented sequentially, even when provided with contextual cues intended to facilitate separation of the speech streams. We discuss the implications of our findings for understanding how infants learn and separate the input when confronted with multiple statistical structures.     

Verbal Abilities in Low and Highly Proficient Bilinguals

The study investigated native language verbal skills among low and highly proficient bilinguals, using the WISC III verbal subtests. Highly proficient bilinguals showed a superiority for almost all verbal subtests. This finding lends support to Threshold Theory which maintains that bilinguals need to achieve high levels of linguistic proficiency before bilingualism can promote cognitive development. Our study also shows that verbal ability underlying proficiency in the native language can be generalized to a foreign language, revealing a causal connection between native and foreign language learning.     

When your heart is in your mouth: the effect of second language use on negative emotions

Research on bilingualism and emotions has shown stronger emotional responses in the native language (L1) compared to a foreign language. We investigated the potential of purposeful second language (L2) use as a means of decreasing the experience of psychological distress. Native Swedish speakers read and answered questions about negative and neutral texts in their L1 (Swedish) and their L2 (English) and were asked to rate their level of distress before or after the questions. The texts and associated questions were either written in the same (within-language), or different languages (cross-language). We found that within-language trials when the text was written in participants’ native language (Swedish–Swedish) resulted in an increase of distress, whilst cross-language trials (Swedish–English) resulted in a decrease of distress. This implies that purposeful second language use can diminish levels of distress experienced following a negative event encoded in one's first language.     

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.     

Bilingual toddlers’ comprehension of mixed sentences is asymmetrical across their two languages

In bilingual language environments, infants and toddlers listen to two separate languages during the same key years that monolingual children listen to just one and bilinguals rarely learn each of their two languages at the same rate. Learning to understand language requires them to cope with challenges not found in monolingual input, notably the use of two languages within the same utterance (e.g., Do you like the perro? or ¿Te gusta el doggy?). For bilinguals of all ages, switching between two languages can reduce the efficiency in real‐time language processing. But language switching is a dynamic phenomenon in bilingual environments, presenting the young learner with many junctures where comprehension can be derailed or even supported. In this study, we tested 20 Spanish–English bilingual toddlers (18‐ to 30‐months) who varied substantially in language dominance. Toddlers’ eye movements were monitored as they looked at familiar objects and listened to single‐language and mixed‐language sentences in both of their languages. We found asymmetrical switch costs when toddlers were tested in their dominant versus non‐dominant language, and critically, they benefited from hearing nouns produced in their dominant language, independent of switching. While bilingualism does present unique challenges, our results suggest a united picture of early monolingual and bilingual learning. Just like monolinguals, experience shapes bilingual toddlers’ word knowledge, and with more robust representations, toddlers are better able to recognize words in diverse sentences.     

Inside bilingualism: Language background modulates selective attention to a talker's mouth

Previous findings indicate that bilingual Catalan/Spanish‐learning infants attend more to the highly salient audiovisual redundancy cues normally available in a talker's mouth than do monolingual infants. Presumably, greater attention to such cues renders the challenge of learning two languages easier. Spanish and Catalan are, however, rhythmically and phonologically close languages. This raises the possibility that bilinguals only rely on redundant audiovisual cues when their languages are close. To test this possibility, we exposed 15‐month‐old and 4‐ to 6‐year‐old close‐language bilinguals (Spanish/Catalan) and distant‐language bilinguals (Spanish/”other”) to videos of a talker uttering Spanish or Catalan (native) and English (non‐native) monologues and recorded eye‐gaze to the talker's eyes and mouth. At both ages, the close‐language bilinguals attended more to the talker's mouth than the distant‐language bilinguals. This indicates that language proximity modulates selective attention to a talker's mouth during early childhood and suggests that reliance on the greater salience of audiovisual speech cues depends on the difficulty of the speech‐processing task.