Laura Bosch

Simultaneous Bilingualism and the Perception of a Language-Specific Vowel Contrast in the First Year of Life:

Behavioral studies have shown that while young infants can discriminate many different phonetic contrasts, a shift from a language-general to a language-specific pattern of discrimination is found during the second semester of life, beginning earlier for vowels than for consonants. This age-related decline in sensitivity to perceive non-native contrasts has been generally attested in monolinguals. In order to analyze the impact of bilingual exposure on the perception of native-sound contrasts and the early building of language-specific contrastive categories, four-monthold and eight-month-old infants from Spanish monolingual, Catalan monolingual and Spanish-Catalan bilingual environments have been tested with a familiarization-preference procedure on a vowel contrast present onlyin Catalan: /e/—/E/. As expected, younger infants were all able to perceive this contrast, independently of the language of exposure. However, by eight months, only infants from Catalan monolingual environments succeeded. Although the decline in sensitivity with the monolingual Spanish group was expected, the results with the bilingual group challenge the view that mere exposure is enough to maintain the capacity to perceive a contrast. An additional experiment at 12 months of age indicated that bilinguals finally regained discrimination. Together these results suggest a specific developmental pattern of perceptual reorganization in bilingual exposure.

A Limit on Behavioral Plasticity in Speech Perception.

It is well attested that we perceive speech through the filter of our native language: a classic example is that of Japanese listeners who cannot discriminate between the American /l/ and /r/ and identify both as their own /r/ phoneme (Goto. H., 1971. Neuropsychologia 9, 317-323.). Studies in the laboratory have shown, however, that perception of non-native speech sounds can be learned through training (Lively, S.E., Pisoni, D.B., Yamada, R.A., Tohkura, Y.I., Yamada, T., 1994. Journal of the Acoustical Society of America 96 (4), 2076-2087). This is consistent with neurophysiological evidence showing considerable experience-dependent plasticity in the brain at the first levels of sensory processing (Edeline, J.-M., Weinberger, N.M., 1993. Behavioral Neuroscience 107, 82-103; Merzenich, M.M., Sameshima, K., 1993. Current Opinion in Neurobiology 3, 187-196; Weinberger, N.M., 1993. Current Opinion in Neurobiology 3, 577-579; Kraus, N., McGee, T., Carrel, T.D., King, C., Tremblay, K., Nicol, T., 1995. Journal of Cognitive Neuroscience 7 (1), 25-32). Outside of the laboratory, however, the situation seems to differ: we here report is study involving Spanish-Catalan bilingual subjects who have had the best opportunities to learn a new contrast but did not do it. Our study demonstrates a striking lack of behavioral plasticity: early and extensive exposure to a second language is not sufficient to attain the ultimate phonological competence of native speakers.

Native-language recognition abilities in 4-month-old infants from monolingual and bilingual environments

This study examined the capacity of 4-month-old infants to identify their maternal language when phonologically similar languages are contrasted, using a visual orientation procedure with a reaction time measure. Infants from monolingual and bilingual environments were compared in order to analyze whether differences in linguistic background affect this behavioral response. In experiment 1 the validity of the procedure was assessed with a pair of phonologically dissimilar languages (Catalan or Spanish vs. English). In experiment 2, 20 infants from monolingual environments tested in a similar language contrast (Catalan vs. Spanish) indicated that discrimination is already possible at that age. Results from experiment 3, using low-pass filtered utterances, suggested that infants can rely on information about supra-segmental features to make this distinction. For the infants growing up in bilingual environments no preference for either of the familiar languages was found. Moreover, when their maternal language was contrasted either with English or with Italian, in both cases the bilingual group showed a similar pattern, consisting of significantly longer latencies for the familiar language. Possible interpretations of this unexpected pattern of results are discussed and its implications for bilingual language acquisition are considered.

Evidence of Early Language Discrimination Abilities in Infants From Bilingual Environments

Previous research data indicate that soon after birth, infants from monolingual families can discriminate utterances drawn from languages that differ prosodically, but discrimination between rhythmically similar languages, such as English and Dutch, has not yet been established by 2 months of age. In the case of bilinguals, the question of how early they can distinguish between the languages of exposure remains unanswered. The goal of this study was to analyze language discrimination capacities in 4-month-old bilingual infants simultaneously exposed to 2 Romance languages belonging to the same rhythmic category, Spanish and Catalan. Using a familiarization-preference procedure, 2 groups of bilingual-to-be infants showed a capacity to discriminate between these 2 familial languages. Moreover, when compared with 2 groups of infants from monolingual environments, the size of the observed effects was the same. These results can be taken as initial evidence of an early capacity to distinguish languages in simultaneous bilingual exposure, thus challenging the hypothesis that language discrimination capacities are delayed in bilinguals.

Building phonotactic knowledge in bilinguals: role of early exposure.

Timing and amount of exposure to a 2nd language in the acquisition of phonotactic restrictions was examined in 4 experiments. In Experiments 1 and 2, 10-month-old monolingual and bilingual Catalan-Spanish infants were presented with nonwords that were phonotactically legal or illegal in Catalan and phonotactically illegal in Spanish. Differences between the 4 groups of infants were obtained as a function of language dominance. In Experiments 3 and 4, adult Spanish-Catalan bilinguals were compared with the same materials. Catalan-dominant bilinguals were more accurate than Spanish-dominant bilinguals in their perception of legal sequences; however, they were not more accurate with illegal sequences. The findings suggest a complex correlation between the pattern of preference and the amount and timing of exposure.

Language-specific stress perception by 9-month-old French and Spanish infants

During the first year of life, infants begin to have difficulties perceiving non-native vowel and consonant contrasts, thus adapting their perception to the phonetic categories of the target language. In this paper, we examine the perception of a non-segmental feature, i.e. stress. Previous research with adults has shown that speakers of French (a language with fixed stress) have great difficulties in perceiving stress contrasts (Dupoux, Pallier, Sebastián & Mehler, 1997), whereas speakers of Spanish (a language with lexically contrastive stress) perceive these contrasts as accurately as segmental contrasts. We show that language-specific differences in the perception of stress likewise arise during the first year of life. Specifically, 9-month-old Spanish infants successfully distinguish between stress-initial and stress-final pseudo-words, while French infants of this age show no sign of discrimination. In a second experiment using multiple tokens of a single pseudo-word, French infants of the same age successfully discriminate between the two stress patterns, showing that they are able to perceive the acoustic correlates of stress. Their failure to discriminate stress patterns in the first experiment thus reflects an inability to process stress at an abstract, phonological level.

Bilingualism Modulates Infants’ Selective Attention to the Mouth of a Talking Face

Infants growing up in bilingual environments succeed at learning two languages. What adaptive processes enable them to master the more complex nature of bilingual input? One possibility is that bilingual infants take greater advantage of the redundancy of the audiovisual speech that they usually experience during social interactions. Thus, we investigated whether bilingual infants’ need to keep languages apart increases their attention to the mouth as a source of redundant and reliable speech cues. We measured selective attention to talking faces in 4-, 8-, and 12-month-old Catalan and Spanish monolingual and bilingual infants. Monolinguals looked more at the eyes than the mouth at 4 months and more at the mouth than the eyes at 8 months in response to both native and nonnative speech, but they looked more at the mouth than the eyes at 12 months only in response to nonnative speech. In contrast, bilinguals looked equally at the eyes and mouth at 4 months, more at the mouth than the eyes at 8 months, and more at the mouth than the eyes at 12 months, and these patterns of responses were found for both native and nonnative speech at all ages. Thus, to support their dual-language acquisition processes, bilingual infants exploit the greater perceptual salience of redundant audiovisual speech cues at an earlier age and for a longer time than monolingual infants.

The Development of Word Stress Processing in French and Spanish Infants

This study focuses on the development of lexical stress perception during the first year of life. Previous research shows that cross-linguistic differences in word stress organization translate into differences in word stress processing from a very early age: At 9 months, Spanish-learning infants, learning a language with variable word stress, can discriminate between segmentally varied nonsense words with initial stress (e.g., níla, túli) and final stress (e.g., lutá, pukí) in a headturn preference procedure. However, French infants, who learn a language with fixed word stress, can only distinguish between initial and final stress when no segmental variability is involved (Skoruppa et al., 2009). The present study investigates the emergence of this cross-linguistic difference. We show that at six months, neither Spanish nor French infants encode stress patterns in the presence of segmental variability (Experiment 1), while both groups succeed in the absence of segmental variability (Experiment 2). Hence, only Spanish infants, who learn a variable stress language, get better at tracking stress patterns in segmentally varied words between the ages of 6 and 9 months. In contrast, all infants seem to be able to discriminate basic stress patterns in the absence of segmental variability during the first nine months of life, regardless of the status of stress in their native language.

Language learning and brain reorganization in a 3.5-year-old child with left perinatal stroke revealed using structural and functional connectivity.

Brain imaging methods have contributed to shed light on the possible mechanisms of recovery and cortical reorganization after early brain insult. The idea that a functional left hemisphere is crucial for achieving a normalized pattern of language development after left perinatal stroke is still under debate. We report the case of a 3.5-year-old boy born at term with a perinatal ischemic stroke of the left middle cerebral artery, affecting mainly the supramarginal gyrus, superior parietal and insular cortex extending to the precentral and postcentral gyri. Neurocognitive development was assessed at 25 and 42 months of age. Language outcomes were more extensively evaluated at the latter age with measures on receptive vocabulary, phonological whole-word production and linguistic complexity in spontaneous speech. Word learning abilities were assessed using a fast-mapping task to assess immediate and delayed recall of newly mapped words. Functional and structural imaging data as well as a measure of intrinsic connectivity were also acquired. While cognitive, motor and language levels from the Bayley Scales fell within the average range at 25 months, language scores were below at 42 months. Receptive vocabulary fell within normal limits but whole word production was delayed and the child had limited spontaneous speech. Critically, the child showed clear difficulties in both the immediate and delayed recall of the novel words, significantly differing from an age-matched control group. Neuroimaging data revealed spared classical cortical language areas but an affected left dorsal white-matter pathway together with right lateralized functional activations. In the framework of the model for Social Communication and Language Development, these data confirm the important role of the left arcuate fasciculus in understanding and producing morpho-syntactic elements in sentences beyond two word combinations and, most importantly, in learning novel word-referent associations, a building block of language acquisition.

El reconocimiento temprano de la lengua materna: un estudio basado en la voz masculina

Resumen El trabajo analiza la capacidad temprana del bebé para reconocer la lengua materna y diferenciarla de otra lengua no familiar. Los bebés estudiados, de 4 meses de edad, proceden de entornos familiares monolingües, en los que se habla el castellano o el catalán. La comparación se establece, pues, entre dos lenguas pertenecientes a una misma clase fonológica (ambas son de ritmo silábico) por lo que la diferenciación puede verse comprometida. El estudio incorpora además la novedad de utilizar la voz masculina y múltiples locutores en la preparación de los materialespara la prueba de discriminación. Los resultados confirman la capacidad del bebé para diferenciar este par de lenguas con independencia del tipo de voz y de la variabilidadde los locutores.