We investigate whether listener age or native speaker status has the biggest impact on the intelligibility of a synthetic New Zealand English voice. The paper presents findings from a speech intelligibility experiment based on a reminding task involving 67 participants. There were no significant differences in the results due to age (young and old adults), however there was for native speaker status. The non- native listeners performed significantly worse than the native listeners in the synthetic speech condition although no differences were found in the natural speech condition. We argue that despite the fact that aging impacts on speech perception, the older native listeners were able to draw on their in depth language model to help them parse the synthetic speech. The non-native speakers do not have such an in depth model to assist them.

Index Terms: speech synthesis intelligibility, older listeners, non-native listeners