Bimodal bilinguals, fluent in a signed and a spoken language, exhibit a unique form of bilingualism because their two languages access distinct sensory-motor systems for comprehension and production. When a bilingual’s languages are both spoken, the two languages compete for articulation (only one language can be spoken at a time), and both languages are perceived by the same perceptual system: audition. Differences between unimodal and bimodal bilinguals have implications for how the brain might be organized to control, process, and represent two languages. In this talk, I highlight recent results that illustrate what bimodal bilinguals can tell us about language processing and about the functional neural organization for language.

An extensive body of research claims that labels facilitate categorisation, highlight the commonalities between objects and act as invitations to form categories for young infants before their first birthday. While this may indeed be a reasonable claim, we argue that it is not justified by the experiments described in the research. We report on a series of experiments that demonstrate that labels can play a causal role in category formation during infancy. Ten-month-old infants were taught to group computer-displayed, novel cartoon drawings into two categories under tightly controlled experimental conditions. These findings demonstrate that even before infants start to produce their first words, the labels they hear can override the manner in which they categorise objects. Yet little is known regarding the nature of the mechanisms by which this effect is achieved. We further describe a neuro-computational model of infant visual categorisation, based on self-organising maps, that implements the unsupervised feature-based approach. The model successfully reproduces experiments demonstrating the impact of labelling on infant visual categorization reported in Plunkett et al. (2008). The results suggest that early in development, say before 12-months-old, labels need not act as invitations to form categories nor highlight the commonalities between objects, but may play a more mundane but nevertheless powerful role as additional features that are processed in the same fashion as other features that characterise objects and object categories.

Language-internal and –external processes in the formation of spatial prepositions in Papiamentu Papiamentu, a Romance-based creole, has a rich, established prepositional system in contrast to other creole languages (Kouwenburg & Murray, 1994). The great majority of these prepositions appear to be transparently derived from their Romance counterparts. However, I will examine two spatial prepositions—riba (>Sp., Port. arriba) and for di (>Port. fora de, Sp. fuera de)—which have semantically expanded to take on additional meanings not exhibited by their Romance counterparts. I will argue that these prepositions exhibit two different processes by showing language-internal processes at work in the expansion of riba and reviewing substratum influence (i.e. language-external) in the case of for di (Maurer, 2005). Finally, I highlight the need to examine lexemes individually as they ostensibly follow similar paths of grammaticalization. Creole languages in general offer a clear warning of attributing synchronic outcomes to one catch-all mechanism.

Bilingual aphasia, defined as a loss of one or both languages in bilingual individuals that results from left hemisphere damage, is of increasing interest worldwide because half the world’s population is bilingual. In the United States, the elderly Hispanic population is the fastest growing ethnic minority (Bureau of the Census, 2006). However, current research on bilingual aphasia cannot inform or recommend the optimal rehabilitation for bilingual aphasic patients (Roberts & Kiran, 2007). For instance, it is not known whether or not rehabilitating one of the patient's languages is sufficient, nor to what extent cross-language transfer occurs after rehabilitation. Several factors contribute to the paucity of research in this area: the multitude of possible language combinations in a bilingual individual, the relative age of acquisition (AoA) and proficiency of the two languages of the bilingual individual, and the effect of focal brain damage on bilingual language representation. In this talk, I will focus on three broad issues, 1) what we understand about brain representation of two languages in normal and brain damaged bilingual individuals, 2) what we understand about the cognitive control of lexical access in bilingual aphasia through analysis of cross-language errors and 3) what we know about cross-language transfer subsequent to rehabilitation in one language. Using four experimental methodologies, fMRI, computational modeling, behavioral analysis of language production and single subject treatment designs, I will provide some insight into the complexities of bilingual aphasia rehabilitation and the various factors that contribute to cross-language transfer in these patients.

What factors affect the coding of two languages in one brain? For over 100 years, researchers have suggested that age of acquisition (when) vs. proficiency (how well) in a particular language play a role in its neural representation. Recent work in my laboratory has explored the influence of these two variables in bilingual language processing using fMRI. Studies have also extended this work by looking at these two factors in monolinguals and in motor skill processing in athletes. The similarities across these domains provide compelling evidence of the link between language and motor skill learning. They are also consistent with an emergentist view in which neural representations arise from a series of interactions at multiple levels. The implications of this conceptualization of language for clinicians and educators alike will be discussed.

What factors affect the coding of two languages in one brain? For over 100 years, researchers have suggested that age of acquisition (when) vs. proficiency (how well) in a particular language play a role in its neural representation. Recent work in my laboratory has explored the influence of these two variables in bilingual language processing using fMRI. Studies have also extended this work by looking at these two factors in monolinguals and in motor skill processing in athletes. The similarities across these domains provide compelling evidence of the link between language and motor skill learning. They are also consistent with an emergentist view in which neural representations arise from a series of interactions at multiple levels. The implications of this conceptualization of language for clinicians and educators alike will be discussed.