Wednesday, April 23, 2008

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.

Contrastive Analysis Hypothesis

The contrastive analysis hypothesis claimed that the difficulty of second language acquisition could be predicted by the degree of difference between the learners first and second language. In chapter nine Brown points out many of the problems with this hypothesis which lead linguists to abandon it. One of the problems with the hypothesis is that it could not predict many of the errors that learners make, and it also predicted interference problems where none would surface.

The most interesting criticism of the contrastive analysis hypothesis for me was the ‘subtle differences” version of the contrastive analysis hypothesis proposed by Oller and Ziachosseiny (Brown p253). They claimed that more interference between the L1 and target language may occur not when there is a large difference between a structure in the two languages but when learners are required to make more subtle distinctions between the languages. In my own experience learning French and Arabic I have found this to be the case. French and English share a lot of vocabulary so there are a lot of cognates as well as false cognates which can cause confusion for learners. Cognates can help in comprehension, but they can cause some problems in production. For example, when I speak French sometimes I may know a French word, but hesitate to use it because I am not sure whether it is the correct French word or whether it is an English word. False cognates can also cause some problems. For example, one mistake that beginning French students often make is to use the French word ‘personnage” to mean ‘person’, but in French this word means ‘character’ as in a character from a story. In Arabic I do not find problems such as these because there are very few cognates between English and Arabic.

Another interesting criticism of the contrastive analysis hypothesis is the case of interlingual errors. These are the types of errors whose source comes from within the target language. For example, overgeneralizing a rule such as the plural ‘s’ and saying ‘mens’ instead of ‘men’. What is interesting to me about this type of error is that it shows how the regularity of the target language is used by the learner. This will lead to some errors, but overall the regularity of the target language will facilitate learning. Most of the time applying the rule of adding an “s’ to form the plural will work. In my experience learning Arabic I have found regular aspects of the language which are quite different than English, but nevertheless make certain aspects of the language easier to learn. For example, Arabic is a language which relies on roots of three or four consonants. These roots have general meanings, and particular words are formed by adding patterns of vowels and certain consonants. The patterns themselves are derivational so also have a meaning. An example of this would be the root “k,t,b” which carries the meaning “write”. Words derived from this root are “kaatib” writer, “maktab” office, “maktaba” library, “kataba” to write. There are several other words with the same root. This pattern of deriving words from cononant roots is very different from English, but is one aspect of the language which makes vocabulary acquisition much easier. It also allows a student to guess the meaning of an unknown word.

While French vocabulary is more similar to English because of the many cognates, sometimes it is more difficult to learn because of the “subtle differences”. Arabic vocabulary shares few cognates with English but the root system of the Arabic language facilitates vocabulary learning even though this type of system does not exist in English.