Speech production modifications produced by competing talkers, babble, and stationary noise

Noise has an effect on speech production. Stationary noise and babble have been used in the past but the effect of a competing talker, which might be expected to cause different types of disruption, has rarely been investigated. The current study examined the acoustic and phonetic consequences of N-talker noise on sentence production for a range of values of N from 1 (competing talker) to infinity (speech-shaped noise). The effect of noise on speech production increased with both the number of background talkers (N) and noise level, both of which act to increase the energetic masking effect of the noise. In a background of stationary noise, noise-induced speech was always more intelligible than speech produced in quiet, and the gain in intelligibility increased with N and noise level, suggesting that talkers modify their productions to ameliorate energetic masking at the ears of the listener. When presented in a competing talker background, speech induced by a competing talker was more intelligible than speech produced in quiet, but the scale of the effect was compatible with the energetic masking effect of the competing talker. No evidence was found of modifications to speech production which exploited the temporal structure of a competing talker. (C) 2008 Acoustical Society of America. [DOI: 10.1121/1.2990705]