Language representation and working memory with bilinguals.

Working memory (WM) plays a crucial role in learning a second language (L2). The ability to repeat words in an unknown language has been observed to predict success in learning that language. Conversely, decreased digit span and inability to repeat pseudowords have been related with failure in L2 acquisition. Not only digit span, but also "word span" and "semantic span" should be considered in WM analysis. In addition to the phonological system, a semantic system is proposed in the WM model for language. In bilinguals, brain activation patterns during WM tasks have been observed to be more complex when using a L2. Processing information in L2 is more demanding, and WM may be less efficient. It can be conjectured that language understanding defects in L2 are at least partially due to this decreased efficiency of WM in its phonological as well as in its semantic subsystem. The reader will be introduced to the basic assumptions of WM. It will be emphasized that WM is significantly involved in the ability to learn a L2. Cross-linguistic differences in digit span will be analyzed. It will be concluded that despite digit span and word span are affected by different variables, "semantic span" may be similar across languages. Words in a L2 function as low frequency words, and hence, semantic search takes longer and WM is less efficient. It will be concluded that in addition to the "phonological system," the WM model should include a "semantic system," involving a "semantic store" and a "semantic search" process.