This weekend I went on a crazy, fun, whirlwind trip to London along with Shelby, Kendall, Jamie, Alyssa, and Merry. While we were only there for a day and half, we managed to see Buckingham Palace, Westminster Abbey, Big Ben, London Bridge, and most of the other major famous sites. As we raced all over the city in the underground, I kept accidentally saying “pardonne-moi” and “désolé” to everyone I bumped into. Only, for the first time in weeks, everyone around us was speaking English. But, even though we all speak English, the way that the locals around us pronounced words and phrases was still different than our own speech.
Of course, from the moment we arrived in England, we were sounded by English accents. Several of us found ourselves fascinated by these accents and, when we were safely out of earshot, we even did our best to imitate them. Yesterday morning as I sat on the train back to Paris, I decided to try to find out what it is about our brain that allows to recognize, use, and understand different accented versions of the same language.
Determining exactly what parts of the brain allow us to understand unfamiliar accents is a difficult task, but there is a growing body of research on this topic. Many of the studies on accent comprehension use functional magnetic resonance imaging (fMRI) to detect changes in brain activity and as subjects listen to sounds or sentences in different accents (Ghazi-Saidi et al., 2015).
A recent review of this research and found that other researchers have identified areas like the left inferior frontal gyrus, the insula, and the superior temporal sulci and gyri as having higher activity when listening to accented speakers produce sounds (Callan et al., 2014; Adank et al., 2015).Interestingly, many of these brain areas are the same regions that have been identified as important for understanding foreign languages (Perani and Abutalebi, 2005; Hesling et al., 2012).Some of these areas that are important for understanding unfamiliar accents – including the insula, motor cortex and premotor cortex – have also been implicated in the production of these accents (Adank et al., 2012a; Callan et al., 2014; Ghazi-Saidi et al., 2015).
Investigating the production of accented speech is also an exciting field of study. Interestingly, one of the main ways we have learned about accent production is through case studies of patients with Foreign Accent Syndrome (FAS). FAS is a fascinating motor speech disorder where patients speak in a different accent than they originally used, typically following brain damage (Keulen et al., 2016). This condition was actually first identified here in Paris by Pierre Marie¹, a French neurologist (Keulen et al., 2016). After recovering from a brain hemorrhage, Marie’s patient had an Alsatian French accent instead of his original Parisian one (Marie, 1907). Since then, nearly 200 cases of this rare disease have been identified (Mariën et al., 2019).
However, it is hard to draw conclusions from individual case studies with just one patient. In a recent metanalysis (a procedure where data from other studies is combined and analyzed), Mariën et al. looked at 112 different published cases of FAS to draw larger conclusions about this rare disease. The authors were particularly interested in cases of FAS that occurred after a stroke, but they analyzed case studies from patients with all different kinds of brain damage.
To review these cases, Mariën et al. first compiled published case studies that reported the cause and symptoms of a patient’s FAS from Pierre Marie’s case in 1907 through October 2016. They then calculated and analyzed the demographic, anatomical, and symptomatic features of these FAS patients to look for larger trends across the different cases.
The authors found that there are statistically significantly more female patients (68% of cases) than male patients in these 112 FAS cases. Additionally, a significant and overwhelming majority (97%) of cases were in adults. In more than half the patients (53%) FAS was present following a stroke.
For those patients who developed FAS following a stroke, the authors also analyzed where in the brain their vascular damage was. The most commonly damaged brain areas (60% of vascular FAS patients) were the primary motor cortex, premotor cortex and basal ganglia which are all important for the physical ability to produce voluntary speech (Brown, Schneider, & Lidsky, 1997). The authors also found that 13% of these vascular FAS patients had damage in the insula, an area that has also been identified as important for accented speech production in studies of healthy subjects (Ghazi-Saidi et al., 2015).
I think FAS is a fascinating disorder, but is important to remember that, like any case studies, these reports have a limited ability to tell us about how healthy people produce accented speech. The naturally occurring brain damage in these FAS patients is not necessarily localized, and other brain areas besides for the primary lesion location could have been affected by the damage. Furthermore, there are some cases of psychological (as opposed to neurological) FAS which complicates our understanding of the onset of this disease (Keulen et al., 2016).
While there is still a lot to learn about understanding how we construct and comprehend accented speech. Studies of FAS patients, particularly large metanalyses like this one, have just begun to identify some of the key brain areas that are reliably indicated in accent production. These findings provide a good starting point for future researchers to analyze these brain areas further and possibly study their role in healthy patients’ accents, which can help us all understand each other a little better.
1 – As a side note for my NBB 301 classmates: Pierre Marie is the “Marie” in Charcot-Marie-Tooth disease, a glial disease that affects Schwann cells. He was also a student of Jean-Martin Charcot and was one of the people depicted in the famous painting A Clinical Lesson at the Salpêtrière that we saw at the Musée de l’Histoire de la Médecine today.
Westminster Abbey: taken by me
Pierre Marie: https://upload.wikimedia.org/wikipedia/commons/thumb/a/a4/PierreMarie.jpg/230px-PierreMarie.jpg
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Brown L, Schneider JS, & Lidsky TI (1997). Sensory and cognitive functions of the basal ganglia. Current Opinion in Neurobiology, 7, 157–163.
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