When Does the Neurological Basis of First and Second Language Processing Differ? Commentary on Indefrey

A large number of studies have been carried out over the last few years investigating whether the neurological represen- tation of language differs between first (L1) and second (L2) language. In a recent review, Stowe and Sabourin (2005) con- cluded that both L1 and L2 typically activate the same areas, particularly the typical language areas (i.e., that there is no con- sistent qualitative difference between the neural architecture supporting processing of the two languages). The evidence sug- gested that this was so even when the L2 was learned relatively late. On the other hand, the extent and intensity of the activa- tion quite frequently differed between the two languages, typ- ically with increased activations for the L2. This was true for word paradigms, phonological processing, and sentence compre- hension. This suggests, instead, a quantitative difference between the processing resources used by the two languages. Particu- larly, it suggests that L2 frequently cannot be processed as ef- ficiently as L1, requiring more "work" from the same processing resources.