TALKER BACKGROUND AND INDIVIDUAL DIFFERENCES IN THE SPEECH INTELLIGIBILITY BENEFIT by

One way talkers can increase intelligibility is by producing clear speech. Though clear speech, as opposed to conversational speech (ConvS), generally increases intelligibility (known as the clear speech intelligibility benefit), not all talkers exhibit the same degree of benefit. Ferguson showed that while intelligibility increased across talkers for clear speech, when looking at individual talkers, the benefit ranged from -12.1 –33.3%. While most talkers were more intelligible during clear speech, some talkers actually became less intelligible. To explain individual differences like these, most researchers have explored acoustic, temporal, and syntactic factors. The current study probes three additional factors, ones relating to talker background: talker experience communicating with nonnative (L2) speakers, talkers’ attitudes toward nonnatives, and talker experience as an L2 speaker. Twenty L2 English listeners transcribed sentences from 20 L1 English speakers as they were produced in ConvS and nonnative directed speech (NNDS; a type of clear speech). Intelligibility scores for ConvS and NNDS were compared to measure individual differences in intelligibility and to calculate the clear speech benefit for each talker. Scores were compared with the talkers’ answers on a questionnaire to determine whether the variables affected the talkers’ intelligibility. Results of the transcription task showed greater overall intelligibility for NNDS than ConvS; however, this was not the case for all talkers. Additionally, talkers varied