Language Acquisition and Development

The study of first- and second-language (L1 and L2, respectively) acquisition has the goal of characterizing the emergence of linguistic structures of a new language by individuals of different ages. More specifically, the field of L1 acquisition studies how infants gradually develop a native language from birth until they become proficient users of a language. L2 acquisition is significantly different in that learners already have an L1 and go on to learn an additional language. One of the most important features of L1 acquisition is that it is an effortless process because the flexibility of toddlers’ brains allows them to learn a language without conscious knowledge or without awareness of its grammatical rules. In contrast, L2 acquisition often happens when learners’ cognitive capacities are not as flexible as children’s, and as a result, language learning requires conscious effort to understand and learn the structure of the target language. Another important distinction is the source of the linguistic input. In the case of L1 acquisition, parents, caregivers, and the surrounding community are the source of the target language and as such provide a rich linguistic environment from which to absorb grammatical [Page 548]information. In contrast, L2 learners are exposed to the target language in a classroom and get more restricted input from teachers and from other peers learning the language.

The discovery that sign languages exhibit the same linguistic organization as spoken languages led to an equally important discovery: Sign language acquisition has striking similarities with the acquisition of spoken languages. Learners of a sign language such as L1 and L2 have to distinguish the minimal constituents of signs to develop a manual phonology; they have to learn how to inflect a sign to change their meaning; and they have to know the order of the different constituents to express an intended meaning. That said, the differences in modality between sign and speech (acoustic vs. manual) also give rise to certain features of language acquisition that are exclusive to sign. The following sections describe some of the most relevant features that characterize sign L1 and L2 acquisition.