An interdisciplinary field: theoretical approaches in SLA
The field of SLA investigates the acquisition of an additional language after the first language or languages have been already learned in life. As such, it seeks to explain human language development by older children, adolescents, and adults across a wide variety of naturalistic, instructed, and mixed contexts. With a history extending over half a century that has been acquisition, SLA continues to be a most porous and interdisciplinary field. Today, it harbours a notable diversity of epistemological approaches. Four theoretical approaches showed tremendous vitality by the close of the twentieth century: cognitive-interactionist, formal linguistic, Vygotskian sociocultural, and usage-based emergentist SLA. SLA in the twenty-first century exhibits novel intellectual influences spurred by the social turn and by new interdisciplinary connections with bilingualism, psycholinguistics, education, anthropology, and sociology. These newer influences have led to the crafting of SLA theories that offer a social re-specification of many SLA interests. (Ortega, 2011: 181. In Simpson (ed)).
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