Dialectal effects in the perception of vowels produced by first and second language speakers : North Carolinian versus Southern Welsh listeners

This paper investigates the effect of listeners' dialect on the perception of vowels. Listeners from North Carolina and South Wales categorized natural tokens of the four English vowels /i/, /I/, /E/ and /ae/ which were produced by speakers of Californian-, Dutch-, Spanish-, and Portuguese-accented English. Randomization tests revealed a significant difference between the listener groups' confusion matrices. Territorial maps were constructed on the basis of logistic regression models that were fitted to each listener group's responses, and they revealed that the differences in categorization were due to differences between the boundaries of the vowel categories of the two listener groups.