ABSTRACT
The length of the message will affect participants' task performance: navigation and readback accuracy, and speech production: accentedness, comprehensibility, fluency and confidence, in a simulated pilot navigation task, in those longer messages will result in a performance detriment on all measures. The prediction here was that the effects of message length would differ for all groups and that the lowest scores for task performance and speech production would be obtained in the group with the lowest level of second language (L2) proficiency. The message length findings support the hypothesis in that longer messages resulted in a performance detriment for all groups; however, the prediction that the lowest scores would be obtained for the lowest proficiency group was only partially supported. Overall, participants' speech was perceived as less comprehensible, less fluent, more accented and less confident-sounding in the Workload condition than in the Clear condition.
