What is Foreign Accent Syndrome?

Foreign accent syndrome (FAS) is speech disorder that causes a sudden change to speech so that a native speaker is perceived to speak with a “foreign” accent. FAS is most often caused by damage to the brain caused by a stroke or traumatic brain injury. Other causes have also been reported including multiple sclerosis and conversion disorder and in some cases no clear cause has been identified.

Speech may be altered in terms of timing, intonation, and tongue placement so that is perceived as sounding foreign. Speech remains highly intelligible and does not necessarily sound disordered.

FAS has been documented in cases around the world, including accent changes from Japanese to Korean, British English to French, American-English to British English, and Spanish to Hungarian.

Some common speech changes associated with FAS include: