One thing that frustrated me a little during my MA studies was that while my Second Language Acquisition class talked about language loss/proficiency changes due to social and cultural factors (e.g. the all-too-common case of a child who speaks an indigenous language as their L1 and then goes to an English-only residential school, partially or entirely losing their proficiency in their L1 as a result), but there was comparatively little discussion of how physiological changes can affect language ability. Not that the social and cultural forces that cause language loss aren’t important to examine, discuss, and criticize, but I often wondered about how, say, Alzheimer’s Disease or a traumatic brain injury might manifest in or affect a multilingual person, as opposed to a monolingual person.
It’s well known that neurological injuries and illnesses can have a profound effect on spoken and written language. Researchers analyzed the writing of the novelist Iris Murdoch (who was portrayed by Judi Dench and Kate Winslet in the film Iris), and found that her final works used markedly simpler language, and employed much more circumlocution (talking around something because you can’t find the exact word — a common symptom of dementia), than the novels she wrote in her cognitive prime. This change in her writing style occurred before she was officially diagnosed with Alzheimer’s in 1995. Scientists also found similar patterns in the works of Agatha Christie, leading them to speculate that the famous mystery novelist may have also suffered from Alzheimer’s or another form of dementia towards the end of her career.
Thus far, research on the effects of neurological injury and illness doesn’t seem to take into account multilingualism very often (though there are numerous studies concerning how multilingualism can delay the onset of dementia, and reduce the risk for developing it). We see from the research on Agatha Christie and Iris Murdoch that dementia robs its sufferers of their language skills in their L1 before it’s even diagnosed, but how does it affect L2, L3, et cetera?
In an article in their 1989 book Bilingualism Across the Lifespan: Aspects of Acquisition, Maturity, and Loss , Kenneth Hyltenstam and Loraine K. Obler (1989) found that bilingual people with aphasia (disturbances in how someone processes or produces language*) displayed a few interesting linguistic characteristics. For one, bilingual sufferers of aphasia often have difficulty moderating which language to use (and keep using) when speaking to someone else (Hyltenstam and Obler, 1989, p. 202). However, Hyltenstam and Obler (1989) say, many studies of multilingual people with neurological illnesses or injuries often mark language mixing as a symptom of dementia/aphasia, and do not consider that such speech behavior might be normal speech for that person, or their speech community as a whole. Perhaps the bellwether, which Hyltenstam and Obler (1989) mention, should be “appropriate” use of languages. In other words, a bilingual English/Spanish speaker code-switching or code-mixing with English may not be a red flag for dementia/aphasia, but a bilingual English/Spanish speaker speaking only English to a monolingual Spanish-speaking companion (whom they know to be monolingual) may be.
A year after Bilingualism Across the Lifespan was published, Obler, along with Susan De Santi, Helene Sabo-Abramson, and Joan Goldberger (1990), wrote an article on the effects of dementia among multilingual individuals (De Santi et al, 1990); De Santi et al (1990) came to a similar conclusion to Hyltenstam and Obler (1989): that a characteristic sign of impairment or decline in multilingual individuals was a breakdown in how they followed the rules of discourse, or communication, in one or more of the languages they speak. “For the healthy bilingual or multilingual speaker…decisions concerning language choice or code-switching are based on sophisticated linguistic and social rules (Grosjean 1982). In dementia…these rules seem to break down” (De Santi et al, 1990, p. 224).
I’ll confess that I’m too cheap to bypass the paywall on De Santi et al’s (1990) article, but I wonder if the discourse difficulties the researchers describe are related to breakdowns in impulse control and judgment that occur in dementia. If a person with dementia lost their ability to follow social norms and unwritten, unspoken rules of interaction (very common in people with dementia), it would make sense that this could cause them to lose sense of the rules of multilingual engagement.
In what I can read in the article, De Santi et al (1990) describe the “rules” which multilingual sufferers of dementia can no longer follow as “constraints” of code-switching, i.e. grammatical forms that multilingual individuals use when they code-switch — for instance, the syntax must be the same in both languages being used in a phrase or sentence (the example De Santi et al (1990, p. 225) use illustrates that “j’ai acheté an American voiture” (I bought an American car) would be incorrect, because adjectives come after nouns in French). So in De Santi et al’s (1990) study, the focus is more on the “innate” rules of grammar and code-switching, not on the social aspects of discourse. Would this give weight to Chomsky’s idea that understanding of grammar is an in-born neurological feature, not something learned and stored in long-term memory, which seems to be more resilient in dementia?
A 1999 study at UCLA by Mendez, Perryman, Poton, and Cummings also found that “cross-language interference” (aberrant use of two languages) was common among bilingual Alzheimer’s patients. In addition, Mendez et al (1999) found that L2 is often the “first to go”, so to speak, when bilingual individuals develop dementia and L1 is preferred and preserved for longer, and will “intrude” into L2 more than the other way around, which is consistent with other patterns of cognitive loss and decline in dementia.
With growing aging populations around the world, growing awareness of the effects of neurological injury and illness, and advances in both neuroscience and linguistics, understanding language’s role in detecting, treating, and living with neurological conditions is more important than ever. And with globalization and increased migration making multilingualism more and more common around the world, understanding the unique needs and struggles of multilingual individuals with neurological conditions also matters a great deal. In the 28 years since Hyltenstam and Obler’s (1989) article, we may have moved forward somewhat on these goals, but there’s still a long way to go.
*The two best known forms of aphasia (there are many, many forms) are named after the areas of the brain that help us process and produce language: Wernicke’s and Broca’s. In Wernicke’s Aphasia, patients have difficulty understanding and processing written and spoken language, though their ability to speak and put together sentences is undiminished — this results in them speaking in “word salad” or fluent sentences that don’t make sense. In Broca’s Aphasia, patients’ receptive skills are unaffected (i.e. they can still understand spoken and written language), but they find it extremely difficult to form full sentences or words. Here are two YouTube videos which demonstrate the speech patterns of people with these types of aphasia:
Day, A. (2016, September 29). Alzheimer’s Early Tell – Issue 40: Learning. Retrieved November 18, 2017, from http://nautil.us/issue/40/learning/alzheimers-early-tell
De Santi S., Obler L.K., Sabo-Abramson H., Goldberger J. (1990) Discourse Abilities and Deficits in Multilingual Dementia. In: Joanette Y., Brownell H.H. (eds) Discourse Ability and Brain Damage. Springer Series in Neuropsychology. Springer, New York, NY DOI: https://doi.org/10.1007/978-1-4612-3262-9_10
Hopkin, M. (2004). Iris Murdochs last book reveals early Alzheimers. News@nature. doi:10.1038/news041129-4
Hyltenstam, K., & Obler, L. K. (1999). Bilingualism across the lifespan: aspects of acquisition, maturity, and loss. Cambridge: Cambridge Univ. Press.
Mendez, M. F., Perryman, K. M., Pontón, M. O., & Cummings, J. L. (1999). Bilingualism and Dementia. The Journal of Neuropsychiatry and Clinical Neurosciences, 11(3), 411-412. doi:10.1176/jnp.11.3.411