These are cases which evoke fascination and wonder: a woman from Virginia who fell down the stairs and woke up speaking in a Russian accent; a German woman involved in a road accident who started speaking her native language with a pronounced British accent.
Foreign accent syndrome (FAS) is a recognised disorder caused by damage to the brain due to trauma or stroke. It is defined as occurring when a person speaks with an accent which is measurably different to their own. FAS is not a motor speech disorder; typically, those affected produce grammatically correct language, with a broad range of sounds and vocabulary.
There is no clear evidence of people speaking a different language after a brain injury; it is accent, not the language itself, which changes. The production of vowel sounds seems to be more affected than that of consonants.
What does this mean for the affected person? A well-known early case of FAS was that of Norwegian woman, Astrid L., who was hit by shrapnel during the Second World War. Following her injury, she started speaking in a German accent, causing her to be turned away from shops and shunned because of the strong anti-German feeling in her country.
In studies of people who have experienced FAS, there is growing recognition of the impact upon the sense of self when a person’s native accent suddenly changes. One interviewee observed: ‘‘Where has the old self gone, and where has the new person come from?”
Researchers at the University of Oxford have carried out extensive work to help understand what part of the brain might be involved in these changes (Gurd & Coleman, 20016). The affected area is almost always the left-brain hemisphere, which is dominant for language, rather than the right. Their work pin-points areas linked to FAS as follows: Broca’s area (frontal operculum and posterior third of the inferior frontal gyrus), premotor cortex, insula, striatum, pallidum, thalamus, brainstem, white-matter pathways such as the internal capsule.
However, it is not fully understood whether accent changes occur because of damage itself, or more subtly, disruption within the feedback processes involved in speech production.
In many cases, damage will not be visible on an ordinary CT scan. Although changes may be evident on an enhanced functional MRI scan, such small lesions can also be present but ‘clinically silent’ in healthy people over the age of 50.
Case studies show that some people return to their normal speaking accent within a duration of about two years; FAS is usually a temporary condition. In one reported case study (M. Lippert-Gruene, 2006), an individual who also experienced amnestic aphasia after a brain injury (difficulty retrieving words) described FAS as helpful, because people assumed she was speaking a second language and tended to be patient and understanding; one language difficulty masked the other.
Although FAS is very rare, with no more than several hundred cases reported in the literature, it does provide a fascinating window into the way language is produced, the processes that occur in the brain and equally, the psychology around the way we speak and the experience for a person who suddenly loses their language identity.
Gurd, J. M., & Coleman, J. S. (2006). Foreign accent syndrome: best practice, theoretical issues and outstanding questions. Journal of Neurolinguistics.
M. Lippert-Gruener, U. Weinert, T. Greisbach & C. Wedekind (2005) Foreign accent syndrome following traumatic brain injury, Brain Injury.
Rosalie A. Perkins , Jack H. Ryalls , Cecyle K. Carson & Janet D. Whiteside (2010) Acoustic analyses of two recovered cases of foreign accent syndrome,APHASIOLOGY.