The Role of Spectral Resolution in Foreign-Accented Speech Perception

Several studies have shown that diminished spectral resolution leads to poorer speech recognition in adverse listening conditions such as competing background noise or in cochlear implants. Although intelligibility is also reduced when the talker has a foreign accent, it is unknown how limited spectral resolution interacts with foreign-accent perception. It is hypothesized that limited spectral resolution will further impair perception of foreign-accented speech. To test this, we assessed the contribution of spectral resolution to the intelligibility of foreign-accented speech by varying the number of spectral channels in a tone vocoder. We also examined listeners' abilities to discriminate between native and foreign-accented speech in each condition to determine the effect of reduced spectral resolution on accent detection. Results showed that increasing the spectral resolution improves intelligibility for foreign-accented speech while also improving listeners' ability to detect a foreign accent but not to the level of accuracy for broadband speech. Results also reveal a correlation between intelligibility and accent detection. Overall, results suggest that greater spectral resolution is needed for perception of foreign-accented speech compared to native speech.