Intelligibility of Foreign-Accented Speech for Older Adults with and without Hearing Loss

Abstract

Numerous studies have demonstrated that the negative effect of noise and other distortions on speech understanding is greater for older adults than for younger adults. Anecdotal evidence suggests that older adults may also be disproportionately negatively affected by foreign accent. While two previous studies found no interaction between foreign accent and listener age, these studies reported no audiometric data and assessed speech understanding in quiet only. To examine the effects of foreign accent, listening condition, and listener age and hearing status on word identification. A cross-sectional descriptive study. Experiments 1 and 2 tested young adults with normal hearing (n = 20 and n = 5, respectively), older adults with essentially normal hearing (n = 20 and n = 10, respectively), and older adults with sloping sensorineural hearing loss (n = 20 and n = 10, respectively). The intelligibility of English words produced by a native speaker of English and by a native speaker of Spanish was assessed. In Experiment 1, word intelligibility was measured in quiet, in noise (+3 dB signal-to-babble ratio, or SBR), and in a telephone filter condition. In Experiment 2, intelligibility was measured in three additional noise conditions (+6, +9, and +12 dB SBR). English words produced by the native speaker of English were significantly more intelligible than those produced by the native speaker of Spanish. While the negative effect of noise was significantly greater for older listeners than for younger listeners, the effect of foreign accent was independent of listener age, listener hearing status, and listening condition. The results suggest that, unlike with other forms of distortion, older adults are not disproportionately affected by foreign accent. This suggests, in turn, that talker-related distortions of the speech signal have a qualitatively different impact on speech perception than distortions that are applied to the signal after it has been produced. The nature of these different types of distortion may be a fruitful area for future investigations of speech understanding in older adults.