Phonological and phonetic marking of information status in Foreign Accent Syndrome

Foreign Accent Syndrome (FAS) is a motor speech disorder in which a variety of segmental and suprasegmental errors lead to the perception of a new accent in speech. Whilst changes in intonation have been identified to contribute considerably to the perceived alteration in accent, research has rarely focused on how these changes impact on the pragmatic use of intonation. However, a greater understanding of the role of intonational changes in FAS and its impact on the functional use of intonation is fundamental to developing appropriate assessment and subsequently treatment strategies for FAS.

This study investigated intonation patterns in speakers with FAS and matched control participants with regard to their ability to signal new and given information (information status) within sentences. A phonetic and phonological perspective was taken with the aim of identifying the characteristics that were compromised in FAS to convey this linguistic function.

Four speakers with FAS and four control participants participated in the speech production experiment. The speech data were assessed perceptually, and examined in relation to the use of the phonetic parameters fundamental frequency (f0), intensity and duration as well as phonological categories, i.e. pitch accents and de-accentuation, using the autosegmental-metrical (AM) framework of intonational analysis.

Both speaker groups employed all three phonetic parameters to differentiate between new and given information. However, groups differed regarding the use of phonological markers, with speakers with FAS frequently placing pitch accents on given information instead of de-accenting these elements. According to the perceptual evaluation, three of the four speakers with FAS had problems signalling information status.

The fact that speakers with FAS marked information status similarly to control speakers at the phonetic level, but failed to do so using phonological categories highlights the importance of assessing phonetic as well as phonological features to gain detailed information about the functional use of intonation in FAS.