Michel Paradis

Bilingualism and Aphasia

Publisher Summary This chapter focuses on aphasia and bilingualism. Recovery is said to be antagonistic when one language regresses as the other progresses. Recovery is said to be successive when one language does not begin to reappear until another has been restored. Successive recovery may also be a part of a selective restitution pattern. The chapter presents a case study of a patient who first recovered from his Bulgarian mother tongue and then from German and Russian, but recovered from neither French nor English. Recovery is said to be selective when the patient does not regain one or more of his languages. It has also been observed that sometimes the language preferentially recovered is neither the mother tongue nor the most fluent language but the language of the patients milieu, that is, the language spoken by the hospital staff. However, no single characteristic of the language preferentially restituted seems to be the determining factor of its recovery.

Alternate antagonism with paradoxical translation behavior in two bilingual aphasic patients

Abstract Two patients presenting a pattern of recovery yet unreported in the literature were observed, one in Paris, the other in Montreal. Both patients alternately suffered severe word-finding difficulties in one language while remaining relatively fluent in the other. They retained good comprehension in both of their languages at all times. They were able to translate correctly and without hesitation from the language they could speak well at the time into the language unavailable for spontaneous use, but were unable to translate from their temporarily poor language (which they understood well) into the language which they could speak quite well at the time.

Language lateralization in bilinguals: Enough already!

All clinical evidence points to the fact that both languages of bilinguals are subserved by the left hemisphere in the same proportion as in unilinguals. Half of the experimental studies have reported no significant difference in lateralization between unilinguals and bilinguals. Those studies that have reported a difference contradict each other with respect to the bilingual subpopulations that are alleged to exhibit differential laterality. In the face of the lack of demonstrated validity of dichotic, tachistoscopic, and time-sharing paradigms in reflecting laterality of language functions in bilinguals, it may be time for neuropsychologists to move on to more productive research.

On the representation of two languages in one brain

Abstract While the study of bilingualism has been steadily gaining important ground for quite some time, in sociolinguistics and most certainly developmental psycholinguistics, the relevance of bilingualism to the neurology of language in particular and to neuroscience in general has only recently been paid much attention to. The reason is because cases of aphasia in bilinguals and polyglots are numerous but the number seen by any individual researcher remains small. For a comprehensive anthology of such cases, see Paradis (1983) . The aim of this paper is to carefully review four kinds of literature, with a threefold purpose. Specifically, (1) the various hypotheses about the lateralization of language functions in bilinguals are identified and their implications for the acquisition of a second language considered. In so doing, (2) other plausible parameters of differential representation of two languages in one brain are examined: the participation of the limbic system during language acquisition and the possible role of sociolinguistic factors. (3) The various hypotheses concerning the intrahemispheric cortical organization of two languages are also investigated. Attempts are made to overcome the weaknesses of two mutually exclusive hypotheses concerning the way a bilingual stores linguistic information; that is, (1) all information is kept in a common store and (ii) information is stored linguistically in separate stores. What has been ascertained so far from the study of aphasia in bilingual patients is that: (1) two languages can be functionally independent; (2) linguistic competence (mnemic traces) is distinct from performance (access to these traces and their actual use); (3) there is a clear dissociation in performance between comprehension and production; (4) there are different components of linguistic structure, each admitting of independent interference in normal bilingual subjects and of selective impairment in aphasic patients; (5) lexical meanings (which are language-dependent) are distinct from experiential and conceptual mental representations (which are language-independent); (6) words are not stored as units but as connected sets of very different kinds of representations; and (7) two languages are not necessarily organized in identical fashion in the brain of all bilingual individuals; indeed, bilinguals vary along a considerable number of dimensions (see Paradis 1984).

Compensatory strategies in genetic dysphasia: Declarative memory

There does not appear to be a consensus in the developmental dysphasia literature as to the characteristics of Specific Language Impairment (SLI). This may be because there are likely to be several different types of developmental dysphasias of widely different etiologies. Converging evidence from epidemiological and twin studies of SLI [ 1, 21 has shown a pattern of occurrence typical of any genetically transmitted trait. Even though at the time this paper goes to press the gene (or genes) associated with the pattern of linguistic deficits discussed here has not yet been isolated, we call the deficit we describe genetic dysphasia and predict that the gene, or genes, involved will eventually be found, as no other explanation is compatible with the data. This is not to claim that there is a gene for morphology or even for grammar. The only claim that we make here is that there is a genetic component in this developmental condition. The expression of a particular gene or set of genes is constrained by a number of environmental factors during fetal development. It (or they) may also affect functions other than language subserved by different parts of the brain [3]. Nevertheless, its manifestations, when expressed, are fairly systematic and predictable, specifically affecting the ability to acquire some types of implicit linguistic competence, particularly the incidental internalization of those aspects of phonology and morphology which are described by linguists as implicit rules. Should the gene(s) never be found, the descriptions of the deficit and of the compensatory strategies that follow would nevertheless remain valid for this population. Equivalent cross-linguistic impairments have been found in speakers of languages other than English as morphologically different as Greek and Japanese. The individuals’ impairment can hardly be attributed to social causes since many of the members of families intensively studied so far (in one case fraternal twins) do not exhibit the impairment and yet are raised in the same environment, eat the same foods, live in the same neighbourhood, are exposed to the same dialect from parents and siblings. Many of the children with a parent with genetic dysphasia do not show signs of abnormal language acquisition despite the fact that they get the same (possibly impaired) language input as their siblings who do demonstrate language impairment. Non-linguistic causes such as specific hearing deficits have been ruled out since it has ben shown that these individuals were perfectly able to make the required phonemic distinctions in discrimination tasks on lexical items involving the same phonemic properties as the deficient morphology [4]. Because there are likely to be several types of SLI with corresponding different etiologies, we shall refer to our subjects as individuals with genetic dysphasia to distinguish them as a

Recent developments in the study of agrammatism: Their import for the assessment of bilingual aphasia

Abstract Recent developments in the study of agrammatism are examined. Each of the various questions generated by the discussion about agrammatism over the past 5 years, from the very nature of the deficit to the nature of its causes and the language-specific realization of its symptoms, creates problems for the assessment of bilingual aphasia. While bilingual aphasia should provide answers to some of the questions about agrammatism, the characteristics of agrammatism in all languages concerned must be known before bilingual aphasia can be meaningfully assessed. The form of the observed deficit may be a function of the specific structure of each language. It is therefore essential to know what the manifestations of the deficit are in each language so as to avoid the erroneous diagnosis of agrammatism in one of the patients languages and of paragrammatism in the other.

Selective crossed aphasia in a trilingual aphasic patient followed by reciprocal antagonism.

After surgical removal of a parasitic cyst in the right prerolandic area, an educated 25-year-old male exhibited obvious deficits in one of his three languages (Gujarati), with no measurable deficits in the other two (French and Malagasy). The patient spoke all three languages fluently before the operation. Gujarati and Malagasy had been acquired in infancy. Gujarati was the language of his parents and relatives. Malagasy the language of the local population. All the patients schooling had been in French, the only language in which he was literate. He used French daily at work. Since the acquisition history for Gujarati and Malagasy was identical, while French had been acquired in a different context, one would have predicted, on the basis of W. Lambert and S. Fillenbaums (1959, Canadian Journal of Psychology, 13, 28-34) hypothesis, that Gujarati and Malagasy should have been equally affected, with French possibly differently so. However, 8 months postoperatively, the patient had regained control of Gujarati, while Malagasy had deteriorated considerably, and his French remained unimpaired. Two years later, the patient had recovered full use of his three languages.

Language and Communication in Multilinguals

The various recovery patterns of bilingual aphasic patients may be accounted for in terms of interference with the normal distribution of inhibitory resources. The differences between unilinguals and bilinguals may be only quantitative, reflecting the extended reliance on metalinguistic knowledge and/or pragmatic competence in the use of their weaker language. Also, one language (or certain items within a language) may be more readily available, depending on the frequency of their use. Distinctions between the linguistic and neurolinguistic levels of description, lexical and conceptual representations, language and verbal communication, implicit linguistic competence, and explicit metalinguistic knowledge will help our investigation of the complex problems posed by bilingual aphasia and the representation of two languages in the same brain.

Generalizable Outcomes of Bilingual Aphasia Research

A number of constructs developed to account for bilingual aphasia phenomena have been advantageously extended to increase our understanding of language representation, processing, breakdown and rehabilitation in unilinguals as well. In particular, focus on the right-hemisphere-based pragmatic component of verbal communicative competence, the activation threshold, the control of resources, the role of emotion in second language acquisition and that of procedural vs. declarative memory, has led to the suggestion that unilinguals are in fact at one end of a continuum, with multilinguals who speak genetically unrelated languages at the other end. No function is available to the bilingual speaker that is not already available to the unilingual, unidialectal speaker. The only difference seems to be the degree of use the speaker makes of each of the relevant cerebral systems.

Principles Underlying the Bilingual Aphasia Test (BAT) and Its Uses.

The Bilingual Aphasia Test (BAT) is designed to be objective (so it can be administered by a lay native speaker of the language) and equivalent across languages (to allow for a comparison between the languages of a given patient as well as across patients from different institutions). It has been used not only with aphasia but also with any condition that results in language impairment (Alzheimers, autism, cerebellar lesions, developmental language disorders, mild cognitive impairment, motor neuron disease, multiple sclerosis, Parkinsons, vascular dementia, etc.). It has also been used for research purposes on non-brain-damaged unilingual and bilingual populations. By means of its 32 tasks, it assesses comprehension and production of implicit linguistic competence and metalinguistic knowledge (which provide indications for apposite rehabilitation strategies). Versions of the BAT are available for free download at www.mcgill.ca/linguistics/research/bat/.