Keiichi Tajima
Robert Port
Dept. of Linguistics, Indiana Univ., Bloomington, IN 47405
Jonathan Dalby
Commun. Disord. Technol., Bloomington, IN 47401
The reduced intelligibility of foreign-accented speech is usually attributed to errors in the positioning of the articulators. But how much would correction of their timing improve intelligibility? One way to estimate this effect is to manipulate the acoustic timing of foreign accented speech. Short English phrases spoken by a native Chinese talker were manually edited so as to align the duration of acoustic segments with tokens of the same phrases spoken by a native English talker. Editing methods included: (i) insertion and deletion of pitch periods, frication noise, and silence, and (ii) amplitude reduction for approximation of nasal segments. A group of native American listeners identified each phrase in a two-alternative forced-choice task: the correct phrase (e.g., ``equal size'') versus a distractor phrase suggested by listening to the Chinese production (``you're concise''). Performance was only slightly above chance for the unmodified tokens, but reached 80% correct for the modified versions. Performance on the native-accented tokens was nearly 100%. Addition of white noise had little effect on performance. These results suggest that improvement in the articulatory timing of non-native speakers might substantially improve intelligibility. [Research supported by subcontract from Communications Disorders Technology, Inc. and NIDCD.]