Insights into rapid adaptation to Spanish-accented English words in younger and older adults

Abstract

Older adults often report difficulty understanding speech produced by non-native talkers. Although numerous studies have described auditory training protocols to improve speech recognition in noise, there are comparatively few studies evaluating auditory training for improving recognition of non-native speech. However, there is evidence that older adults can achieve short-term, rapid adaptation to non-native speech. In this study, a word-level training paradigm was employed, targeting improved recognition of Spanish-accented English. Younger and older adults with normal hearing or hearing impairment were trained on Spanish-accented monosyllabic word pairs containing four phonemic contrasts (initial s/z, initial v/f, final b/p, final d/t) produced in English by multiple male native Spanish speakers. Listeners completed pre-testing, training, and post-testing, over two sessions. While the training protocol failed to elicit any long-term learning for Spanish-accented speech, detailed examination of listeners' performance during the pre-testing revealed patterns of rapid adaptation that appear to vary by phonemic contrast and that may be dependent on the acoustic features of the stimulus. Statistical methods such as growth curve modeling and generalized additive mixed models are employed to describe the patterns of rapid adaptation, and how they vary between listener groups and different stimulus types.