verbal working memory and sla

Recently I have become interested in the relationship between working memory and language acquisition. According to the dominant model of working memory proposed by Baddely and Hitch working memory is divided into separate components. In this model a central executive controls two subcomponents. One, the visuo-spatial sketchpad stores visual and spatial information while the other, the phonological loop, is a limited capacity store of phonological material. The phonological loop is further divided into a short term store where phonological material fades in a short amount of time unless it is refreshed by the other component called the articulatory loop.

Individual capacity of the phonological loop is usually tested by digit span, the maximum number of digits an indivudual can recall, or by nonword repetition. Studies of individuals with deficits in the phonological loop showed that patients with severe impairments in this component of working memory were otherwise able to function normally in cognative tasks.(Baddely, Journal of Communication Disorders, vol 36, 2003). This lead to the hypothesis that the function of the phonological loop is the acquisition of phonologically unfamiliar words, or new vocabulary. Several subsequent studies have found strong correlations between phonological loop capacity and vocabulary in children, and experimental studies have shown that variables known to affect the capacity of the phonological loop impair word-nonword leaning but now the ability to form semantic associations between known word pairs such as “table-rabbit”. (Baddely 2003)

An interesting study was done by Service (Service, E. 1992, Phonology, Working Memory and Foreign language-Learning. Quarterly Journal of Experimental Psychology, Vol. 45) In this Study Service examined the relationship between nonword repetition and the acquisition of English of Finnish Children over a several year period. She found that nonword repetition of nonword conforming to English phonology predicted success in English language classes even after variables such as nonverbal intelligence had been controlled.

This study was interesting to me because it may have implications in second language teaching. With communicative teaching methods there seems to be little room for rote rehearsal of words, as well as more of a focus on pronunciation. It would be interesting to see what benefits there may be in rote rehearsal exercises of new words as well as more attention to the sound system of the target language in the classroom. The hypothesis of Baddely is that working memory allows novel phonological forms to be held briefly while more permanent representations are set up in long term memory. One natural way that the phonological loop maintains phonological forms is through subvocal rehearsal which refreshes the phonological store. Rehearsal and more familiarity of the phonology of the target language may facilitate vocabulary acquisition in the classroom.