The Effectiveness of Clear Speech as a Masker

Purpose: It is established that speaking clearly is an effective means of enhancing intelligibility. Because any signal-processing scheme modeled after known acoustic-phonetic features of clear speech will likely affect both target and competing speech, it is important to understand how speech recognition is affected when a competing speech signal is also spoken clearly. In 2 experiments, the authors investigated whether listeners would experience improved intelligibility when both target and nontarget speech were spoken clearly. Method: Listeners' recognition of sentences in competing sounds was examined in 2 experiments. For both experiments, the target speech was spoken in conversational and clear styles. The competing sounds in Experiment 1 included 2-talker maskers spoken in conversational and clear styles of English or Croatian. The competing sounds in Experiment 2 included 1-talker maskers spoken in clear or conversational styles and temporally modulated white noise maskers shaped to mimic the 1-talker maskers. Results: Performance increased for clear versus conversational targets. No significant differences were found between conversational and clear maskers. Conclusions: If it were possible to implement clear speech through a listening device, it appears that listeners would still receive a clear-speech benefit, even if all sounds (including competing sounds) were (inadvertently) processed to be more clear.