Bulgarian vowel reduction in unstressed position: An ultrasound and acoustic investigation

Abstract

Vowel reduction in Contemporary Standard Bulgarian (CSB) has been variously claimed to involve raising, no change or lowering of the high vowels /iəu/. There is a general agreement that the low vowels /ɛaɔ/ are raised when unstressed. This paper directly measures tongue height using Ultrasound Tongue Imaging (UTI) and relates this measure to the acoustic correlate F1 at vowel midpoint. The six vowels of CSB were paired with respect to frontness (/ɛ, i/, /a, ə/, /ɔ, u/), and the overlap in height of the unstressed lower vowel in each pair was assessed relative to (a) its stressed counterpart and (b) the stressed and (c) unstressed realisations of the lower vowel. There was no evidence of the higher unstressed vowel in each pair being different from its stressed counterpart. The articulatory and acoustic results are not completely aligned, but both diverge from the traditional model of vowel reduction in CSB.