In this book we are mainly coneerried with individual or collecrive language beha- ViOUT in bilingual communities. However, language behaviour is possible because of some sort of underlying competence. People possess implicit knowledge of the language(s) they speak and/or understand, or 10 put fr differently: they have more or less internalized the language. An interesting question, the focus of this chapter, is how are the (WO languages ofbilingual individuals internalized? Do bilinguals difTer from monolinguals in this respect? In the first section we win discuss the problem of neural representation ofthe two languages. Are they localized in the same area or in different areas ofthe brain? Sectien 7,2 deals with the mental representation oftwo languages. In keeping with research in rhis field of study, we present information about the mentallexicon, connected with each language. Here again, the question is, wherher the two languages are menrally or psychologically discrete, with two discrete lexicons, or whether the bilingual individual operates on the basis of one unified mentallexicon. Generally, bilinguals keep their languages separate in language processing, i.e. in speaking and understanding. Does a special mental faculty develop which enables them 10 do this adequately, 10 process the languages without mixing them up? In sectien 7.3 we will pursue this problem.

There is still little information on the issues dealt with in this chapter. Grosjean (1982: 267) says ‘the bilingua! brain is still very rnuch terra incognira ‘. Researchers do not have direct access 10 the brain or the bilingual mind. The question, for example, whether there is one lexicon or two, cannot be answered directly. Possible answers must be inferred from observable phenomena. Furthermore, research results aften are not unambiguous, and there is much disagreement between different authors. Ir is difficult therefore 10 give a coherent picture of the state of the art in this field of research,

The bilingual brain

Ir is generally assumed t hat the left hemisphere ofthe brain is mainly responsible for language processing. This dominanee of the left hemisphere is particularly streng in right-handed males. The question now is whether this also holds for bi!inguals, and whether the two languages are localized in the same area ofthe brain, and share the same neural mechanisms.