Code Switching in Normal and Aphasic Kannada-English Bilinguals.

Code switching is a practice constrained by grammatical principles and shaped by environmental, social and personal influences (Milroy and Wei 1995). There are several factors crucial to understanding of code switching like the community in which it takes place or mode of the bilingual speaker. Some communities accept code switching within a single context as the norm for communicative interactions whereas others maintain a strict distinction between the languages (Heller 1995). It is thus imperative to study code switching in a proper linguistic and cultural context. Language mode is an important factor to be considered in any study on bilingual aphasia. Language mode is the state of activation of bilingual’s languages and language processing mechanisms at a given time (Grosjean 2000). A bilingual can be on a continuum depending on the situation he is in. At one end they may be in monolingual mode where there would be ideally no mixing and at the other end they find themselves in a bilingual mode mixing languages freely (Grosjean 1982). The movement of a bilingual along the continuum results in varying language behaviors. Earlier research paid little attention to language mode but as Grosjean (2000) highlights, it needs to be controlled in any bilingual experiment by evaluating monolingual and bilingual modes on different days with different interlocutors. In the present study an attempt has been made to do so. Bilingual aphasic speakers like normal bilinguals, need to alternate and use context appropriate languages. Sometimes the deficit in linguistic competence may affect this ability to alternate the linguistic codes (Munoz, Marquardt and Copeland 1998). Bilingual aphasics have been seen to combine languages in a variety of ways. They may use several languages together in same utterance (Gloning & Gloning, 1965; Mosner & Pilsch, 1971) or produce the correct name of an object in an unsolicited language (Gloning & Gloning, 1965; Weisenburg & Mcbride, 1935;) even when it is impossible for the same patient to produce the correct name in that language upon request. Junque, Vendrell, Vendrell-Beret and Tobena (1989) and Paradis (1995) suggest that mixing of languages is frequently observed recovery pattern among bilingual aphasics. One of the earliest detailed reports on language mixing was by Perecman (1984) of a 80-year-old male who suffered extensive bilateral temporal hematomes resulting from a car accident. Data was analyzed for different levels (phonological, morphological, lexical-semantic and syntactic) of code switching. She concluded that language boundaries are poorly delineated in polyglot aphasic’s mental grammar and remarked that utterance level mixing and spontaneous translation are abnormal behaviors seen in bilingual aphasics. Grosjean (1985) contradicts these findings by specifying that utterance level mixing is not unique to bilingual aphasics as suggested by Perecman (1984). He pointed out that the interlocutor in the above study was a multilingual who mixed languages and this in turn could have triggered language mixing in subject as a communicative strategy. He identified factors such as language mode, pre morbid language use and test constraints as strategic in any study dealing with language mixing. Hyltenstam (1995) analyzed samples of language mixing from 31 cases of bilingual aphasia reported in literature using Poplack’s syntactic constraints and the MLF (matrix language frame, Myers-Scotton 1993) model. He found that it is reasonable to believe that the code switching of aphasic speakers is structured according to same conversational constraints as in normal speakers. Munoz, Marquardt and Copeland (1998) pointed to methodological shortfalls that comprised data interpretation such as little information about pre morbid language use, presence of bilingual interlocutors, limited samples and lack of controls. In order to overcome these, Munoz, Marquardt and Copeland (1998), compared the code switching patterns of aphasic and neurologically normal bilingual speakers of English and Spanish using Matrix language frame (MLF) model. Communicative difficulties resulting from code switching with