Effects of Talker and Lexical Variability on Speech Perception by “special Populations.”

In order to gain insight into the combined effects of talker, item, and listener related factors, we examined word recognition in two “special populations” using stimuli that were well controlled in terms of inherent lexical difficulty. Experiment 1 investigated recognition of English words by non-native listeners under conditions known to affect native listener word recognition. Experiment 2 investigated the effects of age on phoneme discrimination and word recognition by comparing performance across normal-hearing younger and older adults. Taken together, results from these experiments demonstrated how signaldependent and signal-independent sources of variability combine during spoken language processing. Specifically, we found that the effect of talker variability across items in a list – a signaldependent factor was equivalent across native and non-native listeners, and across younger and older listeners. In contrast, lexical discriminability – a signal-independent factor exerted a particularly strong effect on spoken word recognition for nonnative and elderly listeners.