Speech timing and the perception of foreign accent: the case of Arabic-accented English

This study reports an experiment conducted to examine the contribution of non-native speech timing to the perception of foreign accent. Native English listeners rated utterances produced in English by speakers whose first language was English or Saudi Arabic, for the degree of perceived foreign accent. The utterances were acoustically modified to significantly reduce segmental and intonational information available to the listeners. The listeners were able to distinguish the native and non-native speaker groups in the acoustically degraded utterances. This suggests that the listeners were able to make use of temporal cues, in the absence of segmental and intonational information, to rate the utterances for the degree of foreign accent. To further investigate this, three temporal measures (articulation rate, durational ratio of unstressed to stressed vowels, utterance-final vowel lengthening) were calculated for each utterance to examine their contribution to the overall perception of foreign accent. Among these measures, articulation rate and, to a lesser extent, the durational ratio of unstressed to stressed vowels played a role in cueing the listeners’ perception of foreign accent. However, while the impact of articulation rate on listener ratings varied by speaker group, higher values of the ratio of unstressed to stressed vowel duration, reflecting lower degrees of vowel reduction, consistently predicted foreign accent ratings.