You may have seen cases of foreign accent syndrome (FAS) covered in the news. In 2007, for example, a ten-year-old boy acquired a new accent after undergoing brain surgery. "He went in with a York accent and came out all posh" his mother told the Guardian newspaper. It's generally been thought that FAS arises after damage to brain areas involved in controlling speech, and to date all reported genuine cases have followed brain injury or surgery. But now a team of Belgian researchers led by Peter Marien have documented what they say are the first ever cases of "developmental" FAS in people with no history of brain damage, brain surgery or psychiatric illness.
Case TL was a 29-year-old Dutch-speaking Belgian woman who sought medical help because she'd pronounced words in a strange way since early childhood. Close relatives confirmed she'd always spoken with a strange accent and brain scans revealed no evidence of neurological abnormalities.
Case KL was a 7-year-old Dutch-speaking Belgian boy with specific language impairment, which means that his language abilities lagged behind his other, unaffected mental abilities. As well as exhibiting language delays, KL also spoke with a strange accent, out of keeping with his family background.
Marien's team recorded speech samples from TL and KL and played them, together with samples from native speakers and cases of acquired FAS, to a listening panel of 123 native Dutch speakers. Sixty-two per cent of the panel judged TL to be a non-native speaker of Dutch and 56.4 per cent felt the same way about KL. The majority view was that TL and KL spoke Dutch with a French accent.
Consistent with this, analysis of the speech of TL and KL by a neurolinguist and phonetician, revealed, for example, that their speech was characterised by tongue movements not typical of Dutch speakers, and by use of an uvular trill - a consonant sound associated with French.
The researchers aren't sure of the causes of the FAS in these two cases, but TL's strange pronunciation may reflect a form of speech apraxia, although this really just replaces one label for her condition with another. KL's unusual pronunciation is likely linked to his language impairment in some way, perhaps caused by abnormalities to the cerebellum, a brain region involved in movement control. These case studies appear to demonstrate just how much more we have to learn about how the brain controls speech.
"The observations in this paper require the traditional definition of FAS as an essentially acquired motor speech disorder to be revised to include patients with a developmental speech and language pathology," the researchers said.
Mariën, P., Verhoeven, J., Wackenier, P., Engelborghs, S., & De Deyn, P. (2009). Foreign accent syndrome as a developmental motor speech disorder. Cortex, 45 (7), 870-878 DOI: 10.1016/j.cortex.2008.10.010
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.