Dissociation between speech modalities in a case of altered accent with unknown origin

We present a case of sudden onset, acquired altered accent in the speech of NL, a 48-year-old, left-handed female. NL's typical Standard Southern British English accent was preserved in singing and reading, but altered in recitation, repetition and spontaneous speech. Neuropsychological investigation, impressionistic and acoustic analysis of accented and unaccented speech are documented. The altered accent displays a slower speech rate and longer duration of consonants and vowels. There is evidence for a shift towards syllable-timed rhythm. NL's altered accent displays atypical coordination between voicing and supra-laryngeal articulation, reduced mean and range of F0, and minor differences in vowel space. These features are broadly consistent with other documented cases of Foreign Accent Syndrome, regardless of aetiology. However, NL's profile of preserved and impaired speech does not fit any pattern typically associated with organic neurological disorder. Moreover, left-handed preference may contribute to differences between singing and reading, versus recitation, repetition and spontaneous speech.