Key points are not available for this paper at this time.
Elizabeth Gatbonton, Pavel Trofimovich, Michael Magid, Learners' Ethnic Group Affiliation and L2 Pronunciation Accuracy: A Sociolinguistic Investigation, TESOL Quarterly, Vol. 39, No. 3 (Sep., 2005), pp. 489-511
Gatbonton et al. (Thu,) studied this question.