Bilingual communities are characterized by their social and linguistic heterogeneity, perhaps even more so than monolingual communities. Linguistically, the heterogeneity is evident in the proficiency continuum that develops in the languages involved. The linguist's concern is the study of this continuum, which in the case of Spanish, for instance, as an unofficial language in the United States, reflects processes of simplification and loss.
The question arises whether this attrition occurs only across generations or also throughout the life of an individual, or whether it is the consequence of incomplete language acquisition by children who receive a reduced input in this language and for whom Spanish fulfills a reduced number of functions.
To begin answering this question it becomes necessary to study the simultaneous acquisition of two languages as a first language (also referred to as 2L1, Meisel 1990, or BFLA), in order to identify the linguistic patterns developed before schooling in one (English in the U.S.) begins, which is the time when the Hispanic child begins to receive massive input in this language.
This is not an easy task, however, because the contextual factors that to a large extent shape up the development of child bilingualism are diverse and complex, and lead to different types or degrees of bilingualism. Among these factors are the age at which the child is exposed to the two languages, the frequency with which the languages are spoken at home and in the community, family and community attitudes toward each of the languages and toward bilingualism. Here, I discuss in what ways some of these factors affect the acquisition of grammatical features of Spanish and English.
Studies of BFLA from birth or at least from before age 3 have been done within the framework of the various theories proposed for monolingual acquisition: NATIVIST and CONSTRUCTIVIST approaches. Briefly, nativist theories affirm that children are genetically endowed with a Universal Grammar, a set of linguistic principles common to all languages which, together with language specific parameters, guide acquisition.
By contrast, constructivist theories state that what is innate are cognitive abilities and general learning mechanisms that make possible the learning of language from the language input which the child receives in situated instances of communication. Some of the principles defended by constructivists are that learning is gradual, contextualized and piecemeal; that abstract structures emerge from specific constructions once a CRITICAL MASS is achieved; and that the sequence of acquisition of a grammatical feature is determined by its complexity and frequency in the target language.
Studies of bilingual acquisition are relatively recent, despite their undeniable theoretical and practical value. From a practical perspective, it is necessary to put an end to some myths about bilingual acquisition--such as that it fosters language confusion or that it causes cognitive and language problems. Quite to the contrary, numerous studies have demonstrated that child bilingualism offers cognitive, linguistic and obvious social advantages (e.g. Bialystok 1999, De Houwer 1987, Genesee 2006, Genesee, Nicoladis & Paradis 1995, Meisel 1989, Paradis & Genesee 1996).
From a theoretical perspective, the high frequency of child bilingualism requires that a theory of language acquisition seriously consider bilingual acquisition. Thus, the fundamental goal (though long term) of the research on 2L1 is the development of models that may account for how bilinguals acquire two linguistic systems at a time, and how these two systems are represented in the mind of the bilingual.
Some researchers have observed that the principles put forward by constructivists are valid as well to account for the acquisition of 2L1 (e.g. Gathercole 2007, Rojas Nieto 2003). …