IntroductionThe discipline of communication sciences and disorders seeks to effectively diagnose and treat injuries resulting in damaged speech. Fields such as speech-language pathology, neuropsychiatry, behavioral neuroscience, and psychology examine cases of language impairment as a result of brain injury in order to determine the best plan for rehabilitation as well as the implications for the overall study of the brain and the science of speech.
Though the study of speech and language in monolingual American English speakers is constantly developing, significantly more data has been found on these speakers than on the increasing population of bilinguals. As languages continue to spread across the globe, bilingualism grows more and more prevalent in the United States, and the need for tangible evidence supporting bilingual speech and language treatment and therapy multiplies along its side. The bilingual population has increased by 120 percent since 1990 and continues to grow each year; by 2030 it is estimated that 40 percent of U.S. children will be learning English as their second language (U.S Department of Education & National Institute of Child Health and Human Development, 2003). With this number on the rise, it is imperative to delve deeper into the topic of speech disorders in bilinguals, including the many effects of traumatic brain injury on the comprehension and production of multiple languages. |
Bilingualism in Therapy
Though each speech-language pathologist is required by the American Speech-Language-Hearing Association to have the capabilities to assess and treat bilingual patients, it is often difficult to conduct supposedly "correct" practices with a lack of resources and lack of concrete knowledge. This difficulty may also stem from the false perception that bilingualism is not the “norm” in America, and that it is therefore uncommonly encountered in the profession. Though monolingualism is, at this point in time, most common in the United States, multilingual speech therapy is a necessary service to provide for America's vast multilingual population. More research on bilingual therapy is necessary and has become more so over the years: Roberts (1998) reports that there were only thirty studies published on bilingual individuals with speech and language disorders from 1967-1997, a span of thirty years, with many of these offering little data or containing too small of a sample size to be applicable to a large population (Marerro, Golden, & Espe-Pfeifer, 2002, p. 474). Though additional literature has been published in the twenty-two year period since this 1998 report, there are still few definitive answers regarding bilinguals and speech therapy. It remains a prevalent topic of interest in the research community, with academics still looking to find the best way to provide patient support and, if possible, a return of full language capability.
Traumatic Brain Injury
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Traumatic brain injury is a common occurrence in the United States, accounting for approximately 1.7 million deaths, hospitalizations, or emergency room visits every year (Wauters, Marquardt, & Munoz, 2020, p. 1). Many of these injuries result in damage to the language production and processing centers of the brain, ultimately leading to impaired communication. This is generally caused by lesions to the left hemisphere of the brain, the hemisphere in which speech and language centers are most commonly located.
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Bilinguals with traumatic brain injury (TBI) often have reduced output in both languages, and struggle with pragmatics, similarly to individuals with autism spectrum disorder. Below is an excerpt from the speech of a patient with TBI that demonstrates contextually inappropriate discourse.
“I have got faults and. My biggest fault is. I do enjoy sport. It’s something that I’ve always done. I’ve done it all my life. I’ve nothing but respect for my mother and father and. My sister. And basically sir. I’ve only come to this conclusion this last two months. And. As far as I’m concerned, my sister doesn’t exist.”
(Lorch, 2014, p. 106)
Those whose speech parameters are affected by TBI such as this individual also have difficulty modifying register and concluding complete thought. They often also have difficulty understanding components of language that are strictly pragmatically based, including irony and figurative language.
This video demonstrates some of the cognitive benefits of bilingualism, many of which are useful in recovery from speech disorders caused by TBI.
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HypothesisIn previous decades, it was a commonly held belief by monolingual researchers that the knowledge of more than one language would make recovery from traumatic injury more difficult. Due to the complexity of retrieving more than one language from a damaged brain, as well as the lack of definitive knowledge about bilingualism, most researchers were generally resigned to the idea that those who were multilingual were at a certain cognitive disadvantage.
However, more recent evidence has shown that bilingual individuals have a better chance of recovery of language after brain injury compared to monolingual individuals. The ability to reclaim at least partial control over the comprehension and production of both languages is linked to the structure of bilingual brain matter, the hemispheric bilateralization of language, and the cognitive connections between each of an individual’s languages, all of which are significantly in the favor of bilingual patients. |