Age Of Second Language Acquisition Research Articles

White-matter development is different in bilingual and monolingual children: a longitudinal DTI study.

Although numerous people grow up speaking more than one language, the impact of bilingualism on brain developing neuroanatomy is still poorly understood. This study aimed to determine whether the changes in the mean fractional-anisotropy (MFA) of language pathways are different between bilingual and monolingual children. Simultaneous-bilinguals, sequential-bilinguals and monolingual, male and female 10–13 years old children participated in this longitudinal study over a period of two years. We used diffusion tensor tractography to obtain mean fractional-anisotropy values of four language related pathways and one control bundle: 1-left-inferior-occipitofrontal fasciculus/lIFOF, 2-left-arcuate fasciculus/lAF/lSLF, 3-bundle arising from the anterior part of corpus-callosum and projecting to orbital lobe/AC-OL, 4-fibres emerging from anterior-midbody of corpus-callosum (CC) to motor cortices/AMB-PMC, 5- right-inferior-occipitofrontal fasciculus rIFOF as the control pathway unrelated to language. These values and their rate of change were compared between 3 groups. FA-values did not change significantly over two years for lAF/lSLF and AC-OL. Sequential-bilinguals had the highest degree of change in the MFA value of lIFOF, and AMB-PMC did not present significant group differences. The comparison of MFA of lIFOF yielded a significantly higher FA-value in simultaneous bilinguals compared to monolinguals. These findings acknowledge the existing difference of the development of the semantic processing specific pathway between children with different semantic processing procedure. These also support the hypothesis that age of second language acquisition affects the maturation and myelination of some language specific white-matter pathways.

On extending experimental findings to clinical application: Never too late? An advantage on tests of auditory attention extends to late bilinguals.

On extending experimental findings to clinical application: Never too late? An advantage on tests of auditory attention extends to late bilinguals.

Neural processing of speech in children is influenced by extent of bilingual experience

Language experience fine-tunes how the auditory system processes sound. Bilinguals, relative to monolinguals, have more robust evoked responses to speech that manifest as stronger neural encoding of the fundamental frequency (F0) and greater across-trial consistency. However, it is unknown whether such enhancements increase with increasing second language experience. We predict that F0 amplitude and neural consistency scale with dual-language experience during childhood, such that more years of bilingual experience leads to more robust F0 encoding and greater neural consistency. To test this hypothesis, we recorded auditory brainstem responses to the synthesized syllables ‘ba’ and ‘ga’ in two groups of bilingual children who were matched for age at test (8.4±0.67 years) but differed in their age of second language acquisition. One group learned English and Spanish simultaneously from birth (n=13), while the second group learned the two languages sequentially (n=15), spending on average their first four years as monolingual Spanish speakers. We find that simultaneous bilinguals have a larger F0 response to ‘ba’ and ‘ga’ and a more consistent response to ‘ba’ compared to sequential bilinguals and we demonstrate that these neural enhancements track with years of bilingual experience. These findings support the notion that bilingualism enhances subcortical auditory processing.

Sentence processing in high proficient Kannada–English bilinguals: a reaction time study

The present study aimed at exploring the semantic and syntactic processing differences between native and second languages in 20 early high proficient Kannada–English bilingual adults through accuracy and reaction time (RT) measurements. Subjects participated in a semantic judgement task (using 50 semantically correct and 50 semantically incorrect sentences) and a syntactic judgement task (using 50 syntactically correct and 50 syntactically incorrect sentences) in both Kannada and English. The stimuli were presented through DMDX software and the subjects were asked to respond by pressing keys in the DMDX software. The accuracy and RTs were measured and compared within and between languages. Results revealed that accuracy rate was better in L1 than in L2 for all three types of sentences, while the overall speed of processing was better in L2 than in L1 across three types of sentences. Results also revealed that participants processed semantic violations with greater accuracy and speed of processing compared to syntactic violations. These results support the good enough approach to language processing which assumes that the sentence processing takes place at shallow level. The results are discussed in relation to the factors such as age of second language acquisition, proficiency levels and exposure levels in bilinguals.

The Babylonian benefit: Neurological research shows that being bilingual enhances mental performance and may protect from Alzheimer's disease.

The Babylonian benefit: Neurological research shows that being bilingual enhances mental performance and may protect from Alzheimer's disease.

Age of second language acquisition affects nonverbal conflict processing in children: an fMRI study.

BackgroundIn their daily communication, bilinguals switch between two languages, a process that involves the selection of a target language and minimization of interference from a nontarget language. Previous studies have uncovered the neural structure in bilinguals and the activation patterns associated with performing verbal conflict tasks. One question that remains, however is whether this extra verbal switching affects brain function during nonverbal conflict tasks.MethodsIn this study, we have used fMRI to investigate the impact of bilingualism in children performing two nonverbal tasks involving stimulus–stimulus and stimulus–response conflicts. Three groups of 8–11-year-old children – bilinguals from birth (2L1), second language learners (L2L), and a control group of monolinguals (1L1) – were scanned while performing a color Simon and a numerical Stroop task. Reaction times and accuracy were logged.ResultsCompared to monolingual controls, bilingual children showed higher behavioral congruency effect of these tasks, which is matched by the recruitment of brain regions that are generally used in general cognitive control, language processing or to solve language conflict situations in bilinguals (caudate nucleus, posterior cingulate gyrus, STG, precuneus). Further, the activation of these areas was found to be higher in 2L1 compared to L2L.ConclusionThe coupling of longer reaction times to the recruitment of extra language-related brain areas supports the hypothesis that when dealing with language conflicts the specialization of bilinguals hampers the way they can process with nonverbal conflicts, at least at early stages in life.

Language use affects proficiency in Italian–Spanish bilinguals irrespective of age of second language acquisition

The role of age of acquisition (AoA) in reaching native-like proficiency in second language is controversial. The existence of a critical period and the effect of AoA have been questioned by studies testing lexical and/or morphosyntactic skills, and by functional brain exploration. The aim of this study was to verify the effect of AoA and language practice on proficiency in a bilingual pragmatic task and its relationship with cognitive skills. The study involved a group of Italian–Spanish bilinguals, classified according to their AoA and language use. All participants performed a pragmatic bilingual test and a battery of cognitive tests. A multivariate analysis showed significant effects of language use and cognitive skills and a non-significant effect of AoA. These results indicate that continued language practice is a major factor influencing high bilingual proficiency, irrespective of AoA, suggesting that proficiency may be weakened when bilingual experience becomes occasional or ceases.

Adults’ and 8‐Year‐Olds’ Learning in a Foreign Word Repetition Task: Similar and Different

Although the significance of age in second language acquisition is one of the most hotly debated issues in the field, very few studies have directly addressed age differences in the language learning process. The present study investigated learning in a foreign‐word repetition task. Young Finnish adults and 8‐year‐olds repeated back Korean words. Some words occurred once whereas others occurred five times. After the session, a surprise old/new recognition task was administered. Both groups’ repetition accuracy improved for recurring but not nonrecurring words. Latencies got shorter for all words. The groups were reliably able to recognize recurring but not nonrecurring words. However, the adults performed substantially better in this memory task with an explicit component. No advantages for children were detected.

Factors affecting the variability of the central mechanisms for maintaining bilingualism

The article discusses the probable role of many factors that determine the individual variety of the neurophysiological mechanisms that provide the opportunity to learn and use fluently two or more languages. The formation of the speech function is affected by both the general factors for bilinguals and monolinguals, as well as by the specific characteristic of bilingualism. General factors include genetic and environmental impacts explaining the diversity of individual options for the development of the morphofunctional organization of the speech function. Bilinguals, obviously, have an even wider variation of the central maintenance of speech ability, due to the combination of different conditions that influence the language environment, which include the age of second language acquisition, the language proficiency, the linguistic similarity of the languages, the method of their acquisition, intensity of use, and the area where each language is used. The influence of these factors can be mediated in different ways by the individual characteristics of the bilingual’s brain. Being exposed to two languages from the first days of life, the child uses for the development of speech skills the unique features of the brain that exist only at the initial stages of postnatal ontogenesis. At an older age, mastering a second language requires much more effort, when, in the course of maturation, the brain acquires new additional possibilities but permanently loses that special “bonus” that nature gives to a small child only in the first months of life. Large individual variability patterns of activation of the cortex during verbal activity in older bilinguals, compared with the younger ones, allows us to assume that the brain of the older bilingual mastering a new language is forced to manipulate a large number of backup mechanisms, and this is reflected in an increase in the variation of the cerebral processes responsible for speech functions. In addition, there is a serious reason to believe that learning a second language contributes to the expansion of the functional capabilities of the brain and creates the basis for successful cognitive activity.

Neural convergence for language comprehension and grammatical class production in highly proficient bilinguals is independent of age of acquisition

In bilinguals, native (L1) and second (L2) languages are processed by the same neural resources that can be modulated by age of second language acquisition (AOA), proficiency level, and daily language exposure and usage. AOA seems to particularly affect grammar processing, where a complete neural convergence has been shown only in bilinguals with parallel language acquisition from birth. Despite the fact that proficiency-related neuroanatomical differences have been well documented in language comprehension (LC) and production, few reports have addressed the influence of language exposure. A still unanswered question pertains to the role of AOA, when proficiency is comparably high across languages, with respect to its modulator effects both on LC and production. Here, we evaluated with fMRI during sentence comprehension and verb and noun production tasks, two groups of highly proficient bilinguals only differing in AOA. One group learned Italian and Friulian in parallel from birth, whereas the second group learned Italian between 3 and 6 years. All participants were highly exposed to both languages, but more to Italian than Friulian. The results indicate a complete overlap of neural activations for the comprehension of both languages, not only in bilinguals from birth, but also in late bilinguals. A slightly extra activation in the left thalamus for the less-exposed language confirms that exposure may affect language processing. Noteworthy, we report for the first time that, when proficiency and exposure are kept high, noun and verb production recruit the same neural networks for L1 and L2, independently of AOA. These results support the neural convergence hypothesis.

What is the impact of age of second language acquisition on the production of consonants and vowels among childhood bilinguals?

This study investigated bilinguals’ ability to produce language-specific acoustic values for consonants and vowels that are highly similar across the two languages. To investigate this ability, we targeted early bilinguals who had acquired two languages before the age of 12 and continued to use both languages on a daily basis. These adult bilinguals were separated into two groups: simultaneous bilinguals (or nearly so) who acquired both languages by their third year, and sequential bilinguals who acquired their second language between the ages of 8 and 12 years. Their speech production was studied through an acoustic analysis of stop consonants (voice onset time) and vowels (formant structure). Despite the differences in age of acquisition, these bilinguals used both languages on a regular basis at work and at home and were very proficient in both languages. In contrast to other early bilinguals who undergo a change in language dominance from their first language to their second, the participants in this study maintained relatively balanced abilities in both languages. This study revealed that childhood bilinguals can maintain contrasts across their two languages, even for very similar phonemes.

Memory for emotional words in bilinguals: Do words have the same emotional intensity in the first and in the second language?

Emotionally charged words are usually better remembered than neutral words. In the current study we focused on memory for emotional words in bilinguals and examined the influence of some variables that might modulate the effect of emotionality of second-language words on recall. We tested memory for positive, negative and neutral words of two groups of proficient bilinguals of Spanish and Catalan who had acquired the second language early in life in an immersion context and who differed in their language dominance. We also tested a group of proficient Spanish–English bilinguals who had learned the second language later in life in an instruction setting. The three groups showed a superiority in recall for emotional words that was of the same magnitude in their first as in their second language. These results suggest that neither language dominance, nor the type of context, the age of second language acquisition, or the similarity between languages, seem to have any effect on memory for emotional words in the second language. They also indicate that, at least in proficient bilinguals, and when memory tasks are used, words seem to have the same emotional intensity in the first and in the second language.

Carpet or Cárcel: The effect of age of acquisition and language mode on bilingual lexical access

Lexical access was examined in English–Spanish bilinguals by monitoring eye fixations on target and lexical competitors as participants followed spoken instructions in English to click on one of the objects presented on a computer (e.g., ‘Click on the beans’). Within-language lexical competitors had a phoneme onset in English that was shared with the target (e.g., ‘beetle’). Between-language lexical competitors had a phoneme onset in Spanish that was shared with the target (‘ bi gote’, ‘mustache’ in English). Participant groups varied in their age-of-acquisition of English and Spanish, and were examined in one of three language modes (Grosjean, 1998, 2001). A strong within-language (English) lexical competition (or cohort effect) was modulated by language mode and age of second language acquisition. A weaker between-language (Spanish) cohort effect was influenced primarily by the age-of-acquisition of Spanish. These results highlight the role of age-of-acquisition and mode in language processing. They are discussed in comparison to previous studies addressing the role of these two variables and in terms of existing models of bilingual word recognition.

Bilingualism and Attention: A Study of Balanced and Unbalanced Bilingual Deaf Users of American Sign Language and English

Early deafness is thought to affect low-level sensorimotor processing such as selective attention, whereas bilingualism is thought to be strongly associated with higher order cognitive processing such as attention switching under cognitive load. This study explores the effects of bimodal-bilingualism (in American Sign Language and written English) on attention switching, in order to contrast the roles of bilingual proficiency and age of acquisition in relation to cognitive flexibility among deaf adults. Results indicated a strong high-proficiency bilingual advantage in the higher order attention task. The level of proficiency in 2 languages appears to be the driving force for cognitive flexibility. However, additional data are needed to reach conclusive interpretation for the influence of age of second language acquisition on higher order attention-switching ability and associated cognitive flexibility.

Neural circuitry of the bilingual mental lexicon: Effect of age of second language acquisition

Numerous studies have proposed that changes of the human language faculty caused by neural maturation can explain the substantial differences in ultimate attainment of grammatical competences between first language (L1) acquirers and second language (L2) learners. However, little evidence on the effect of neural maturation on the attainment of lexical knowledge in L2 is available. The present functional magnetic resonance study addresses this question via a cross-linguistic neural adaptation paradigm. Age of acquisition (AoA) of L2 was systematically manipulated. Concrete nouns were repeated across language (e.g., French–German, valise suitcase–Koffer suitcase). Whereas early bilinguals (AoA of L2 < 3 years) showed larger repetition enhancement (RE) effects in the left superior temporal gyrus, the bilateral superior frontal gyrus and the right posterior insula, late bilinguals (AoA of L2 > 10 years) showed larger RE effects in the middle portion of the left insula and in the right middle frontal gyrus (MFG). We suggest that, as for grammatical knowledge, the attainment of lexical knowledge in L2 is affected by neural maturation. The present findings lend support to neurocognitive models of bilingual word recognition postulating that, for both early and late bilinguals, the two languages are interconnected at the conceptual level.

The age of second language acquisition determines the variability in activation elicited by narration in three languages in Broca’s and Wernicke’s area

It is generally accepted that the presence of a second language (L2) has an impact on the neuronal substrates build up and used for language processing; the influence of the age of L2 exposure, however, is not established. We tested the hypothesis that the age of L2 acquisition has an effect on the cortical representation of a multilingual repertoire in 44 multilinguals with different age of exposure to a L2 (simultaneous or covert simultaneous exposure to L1 and L2, sequential acquisition of L1 and L2 between 1 and 5 years, late learning of L2 after 9 years of age) and all fluent in a late learned L3. Regional activation in a language production task showed a high in-between-subject variability, which was higher than within-subject variability between L1, L2, and L3. We, therefore, performed a single subject analysis and calculated the within-subject variance in the numbers of activated voxels in Broca’s and Wernicke’s area. Subjects with early exposure to L2 showed low variability in brain activation in all three languages, in the two early as well as the late learned language. In contrast, late multilinguals exhibited higher variability. Thus, cerebral representation of languages is linked to the age of L2 acquisition: early exposure to more than one language gives rise to a language processing network that is activated homogeneously by early and late learned languages, while the inhomogeneous activation in late multilinguals indicates more independent access to the multilingual repertoire. Early passive exposure to L2 results in the same low variance as active bilingual upbringing. Variability in local brain activity increases progressively from the simultaneous to late L2 exposure, indicating a gradual transition from the mode of early bilingual language representation to that of late ones.

Pearls &amp; Oy-sters: Selective postictal aphasia

Ictal and postictal language dysfunction is common and strongly predictive of language laterality in monolingual patients. For bilingual patients, selective dysfunction has been reported for a single language with focal cerebral lesions, electrical brain stimulation, and intracarotid sodium amytal. Two right-handed Ukrainian-English bilingual patients with left perisylvian structural lesions, late onset complex-partial seizures, and postictal aphasia for English are presented and discussed with regard to mechanisms of selective aphasia and factors contributory to language lateralization in bilingual patients. Ukrainian was the native language of both patients with English acquired after 7 years of age. Regular/video-EEG showed left temporal epileptogenesis. A 56-year-old man, who had a left hemorrhagic stroke at age 50 and had not spoken Ukrainian for 40 years, was unable to speak English for approximately 20 minutes postictally but had global preservation of Ukrainian. A 71-year-old woman, who had a left temporal epidermoid cyst and had not spoken Ukrainian since childhood, had 10- to 15-minute postictal expressive aphasia in English but not Ukrainian and preservation of comprehension in both languages. These cases are instructive and consistent with the literature on cerebral organization of language in bilingual individuals. For both patients, postictal aphasia with preservation of Ukrainian is consistent with findings from clinical and experimental studies indicating that later age of second language acquisition (>6 years) rather than language proficiency is a primary factor in language laterality. Second, global aphasia in the man with a late lesion vs expressive aphasia with preservation of comprehension of English in the woman with a prenatal/early lesion is consistent with the atypical language laterality described for individuals with left-sided lesions sustained prior to age 5. Although neither Wada test nor fMRI was done to assure left hemisphere laterality of spoken Ukrainian and English, this is probable, and the selective postictal aphasia observed for both patients is consistent with the differential intrahemispheric organization reported for the two languages of bilingual individuals. Possible mechanisms of selective postictal aphasia, e.g., active inhibition, and differences in language networks in bilingual patients are discussed.

The effect of linguistic proficiency, age of second language acquisition, and length of exposure to a new cultural environment on bilinguals' divergent thinking

The study argues that, in addition to advantages in conscious attention-demanding processing, bilinguals may also exhibit enhanced unconscious divergent thinking. To investigate this issue, the performance of Russian–English bilingual immigrants and English monolingual native speakers was compared on the Abbreviated Torrance Test for Adults, which is a traditional assessment tool of divergent thinking. The study reveals bilinguals' superiority on divergent thinking tasks that require the ability to simultaneously activate and process multiple unrelated concepts from distant categories. Divergent thinking was facilitated by bilinguals' proficiency in two languages, the age of acquisition of these languages and the length of exposure to the new cultural settings that accompanies the acquisition of a new language. A specific architecture of bilingual memory in which two lexicons are mutually linked to the shared conceptual system is theorized to facilitate the functioning of the language mediated concept activation, thereby encouraging bilinguals' divergent thinking performance.

IMAGES OF THE MULTILINGUAL BRAIN: THE EFFECT OF AGE OF SECOND LANGUAGE ACQUISITION

Is it the age of second language acquisition (AoA) that primarily determines the manner of cerebral representation of multiple languages in the brain, or is it proficiency? Here, we review recent neuroimaging studies that aimed at investigating AoA effects by comparing early with late (usually with L2 acquisition onset after 6 years of age) bilinguals during a variety of language tasks on a number of languages. Most studies did indeed report AoA effects. Of particular interest is that the region mainly found to functionally differ between early and late bilinguals is the left inferior frontal gyrus, which was modulated during syntactic processing, word generation, and sentence generation. Additionally, differences were observed in gray-matter density of the posterior parietal cortex as well as in right-hemisphere involvement. Interestingly, despite some convergence of findings from a localizational point of view, underlying causes of organizational and functional differences for the effect of AoA on bilingual language processing still remain to be uncovered. Hypotheses currently used for explaining activation differences are described (notably cortical efficiency, executive control, neuroanatomical changes, and right-hemisphere involvement) in relation to AoA and language proficiency.

Performance of Bilingual Speakers on the English and Spanish Versions of the Hearing in Noise Test (HINT)

This study compared the performance of bilingual participants on the English and Spanish versions of the Hearing in Noise Test (HINT). The participants were divided into an early bilingual (EB) group and a late bilingual (LB) group based on age of second-language acquisition. All participants acquired Spanish as their first language (L1) and English as a second language (L2). Care was taken to ensure that all participants demonstrated at least a "good competence level" for self-rated speaking, understanding, reading, and writing skills in both English and Spanish. Results revealed superior performance on the Spanish HINT versus the English HINT in both quiet and in noise for both groups of participants. Significant differences in performance were noted for the EB versus the LB participants. A number of possible explanations for superior performance in L1 are provided, and implications for educating students in their L2 are discussed.