Second language acquisition
Second language acquisition (SLA) refers to both the process and study of developing the ability to use a language other than the native tongue. Research focuses on the extent to which people coming to a second or subsequent language (L2, L3 and so on) develop competence in the language like that of a native speaker, and how similar the acquisition process is to first language acquisition. Where differences are identified, researchers seek to explain what is responsible - for example, whether there is a biologically-based 'critical period' that prevents acquisition after a certain age, or what social or psychological factors, such as exposure to written language, may account for non-nativelike attainment.
Though the study of SLA is often viewed as part of applied linguistics, it is typically concerned with the language system and learning processes themselves, whereas applied linguistics may focus more on the experiences of the learner, particularly in the classroom. Additionally, SLA has mostly examined naturalistic acquisition, where learners acquire a language with little formal training or teaching.
Investigating second language acquisition
Three fundamental issues in SLA today are:
- The extent to which the acquisition of a second language is similar to L1 acquisition;
- Why ultimate attainment in a second language typically falls short of a native speaker's competence (fossilisation);
- Why second language performance and ultimate attainment are highly variable across native language, context of acquisition and individual speakers.
Modern research on L2 acquisition is rooted in contrastive analysis, a viewpoint popular in the 1950s and which sought to explain and predict errors in language learning based on a comparison of the grammar and phonology of the learner's L1 versus the 'target' L2. Though contrastive analysis mostly gave way to theories of L2 acquisition that better-reflected new insights from modern linguistics, psychology and education, it continues to be a tool for spotting potential problems for teaching in the classroom, and as a potential explanation for errors in naturalistic performance - i.e. the understanding and production of spontaneous language by learners.
Error analysis was a component of contrastive analysis, sometimes known as the 'weak' version of the contrastive analysis hypothesis. The 'strong' version sought to predict rather than explain errors, using the differences between the learners' first and second languages.
Critical period hypothesis
A widespread view of second language acquisition is that the ability to fluently use an L2 is lost or significantly declines once a learner is beyond a certain age. This phenomenon is particularly noted in L2 phonology and pronunciation, where it said that it is difficult or impossible for older learners to gain a 'perfect' or even reasonably native-like L2 accent. In the terminology of SLA research, learners usually fossilise, i.e. stop somewhere short of nativelike proficiency, with their subsequent performance apparently impervious to correction.
In actuality, this issue is possibly the most disputed in all of SLA, with some researchers, particularly in applied linguistics, backing the view that a biologically-based 'critical period' for L2 acquisition exists, with others, often with a background in formal linguistics, pointing to other factors outside the maturation of the body and brain as potential explanations.
Literacy and language acquisition
The effect of literacy on language acquisition has become a focal point of research, particularly since the 1990s. Literacy usually helps learning, such as by providing greater access to new vocabulary through written information, and learners who read a lot do better on judging the grammaticality of sentences. Literacy is gradually being identified as a key factor in language processing skills, i.e. literacy positively and negatively affects how well people interpret grammatical patterns, acquire the accent of another language, or perform in tasks involving the manipulation of linguistic utterances. This may account for some of the effects of the critical period hypothesis, for example.
Effect of literacy on second language phonology
Studies have revealed evidence of a negative effect of (often alphabetic) literacy on the acquisition of phonology, i.e. a possible development or maintenance of 'foreign accent'. This may be caused by literate learners wrongly assuming that the written form is a faithful representation of the pronunciation, or because learners' awareness of sounds that their developing spoken language production would initially filter out is increased by exposure to writing, forcing them to produce deviant pronunciations to incorporate these sounds. For example, learners whose native languages do not allow syllable-final consonants may be more likely to produce forms like [ka] for cat without exposure to writing, just as children acquiring English as a first language typically do. However, the written forms shows them that [t] must be pronounced, so an extra vowel is added (epenthesis) as in [katə], which may persist. Acquisition without literacy may avoid those errors, leading to the more target-like [kat] when the learner has acquired final consonants.