Foreign Accent and Speech Distortion

Speech distortion is defined broadly as any operation that evokes inappropriate behavior by a listener in response to speech. Two categories of distorting operations are distinguished: (1) response-independent, in which the transfer function applied to the original speech signal is not determined by the probable response of the listener (e.g., masking, filtering); and (2) response-dependent, in which the distorting operation is related to the probable response of the listener during undistorted transmission and therefore may be specified in linguistic terms (e.g., foreign accent). Two experiments examine the effects and interactions of these two types of distortion. Twenty-four Midwest Americans listened to recorded articulation lists rendered by one American and three foreign-born speakers under eight conditions of masking and filtering. Reducing the speech to noise ratio to 20 dB or the transmission bandwidth to 500 cps yields approximately 50% reduction in word articulation for both native and foreign accent speech. The latter was approximately 40% less intelligible than native speech under all experimental conditions.