The effect of a non-native accent in Dutch on speech intelligibility

Abstract

It is well known that second-language talkers are usually less intelligible than native talkers, especially under adverse listening conditions. Background noise tends to influence the intelligibility of foreign accented speech more profoundly than unaccented speech. In order to quantify this effect, speech reception threshold (SRT) experiments were carried out using Dutch speech by American, German, Polish, Chinese and (native) Dutch talkers (15 speakers, 3 talkers per language background). The experience with the Dutch language varied between talkers from 3 months to 28 years. Ten Dutch university students participated as listeners. In order to obtain 50% sentence intelligibility, non-native talkers were found to require a 0–3-dB better speech-to-noise ratio than native talkers do. A significant correlation between self-reported proficiency and SRT-score was observed (R=0.78). Also, an objective estimate of the degree of foreign accent of the individual speakers was obtained by means of a pairwise comparison experiment, in which 19 native Dutch listeners participated. The accent ratings which were obtained (after Thurstone normalization) were also significantly correlated with the SRT-scores (R=0.85). The conclusion may be drawn that the effect of noise on the intelligibility of foreign accented speech can be predicted quantitatively from easily obtained measures of perceived foreign accent.