Effects of Melodic Contour on Sung Speech Intelligibility in Noisy Environments in Musicians and Nonmusicians

Using songs to facilitate speech processing in noisy environments seems appealing and practical. However, current research suggests otherwise, possibly due to the simplicity of sung speech contours. This study investigates the effects of contour tonality on sung speech intelligibility in noisy environments. A cohort of 20 trained musicians and 20 nonmusicians were tested on the intelligibility of Mandarin sentences sung on tonal, atonal, and fixed-pitch melodies or normally spoken under three signal-to-noise ratios (SNRs: −3, −6, and −9 dB). Perceptual musical skills related to speech-in-noise perception were also assessed. Results showed that overall speech-in-noise intelligibility decreased as the SNR decreased, with spoken speech being more intelligible than sung speech. Sung speech intelligibility was higher for fixed- than variable-pitch contours, with no difference between tonal and atonal melodies. No musician advantage was reported for spoken speech. Musicians, nonetheless, outperformed nonmusicians in identifying sung speech across all melodic contour types. Moreover, the musician sung speech advantage correlated with enhanced music perception abilities on pitch and accent. These results suggest that musicians have an advantage in sung speech in noisy environments. However, melody tonality provided no additional benefits, suggesting that imposing tonality on sung speech does not improve speech perception in noisy environments.