This article presents the results of an acoustic study of unstressed vowels in two agglutinative languages – Even and Evenki. Unstressed positions of vowels were determined according to the rules of stress placement set forth for the Even language in Lebedev, 1978 ; Novikova, 1991 and the Evenki language Konstantinova, 1960. During the analysis, the measurements of the first and second formants (FI and FII respectively) and duration for the unstressed vowels were performed using PRAAT. The obtained data were compared with the corresponding values for the stressed vowels in the root syllable of a word in both languages. First, it was found that vowel quantity and quality reduction in noninitial syllable in a word was a common phenomenon for both languages. The second finding was that during the reduction in Even, labialized and nonlabialized allophones of the phoneme /ɛ/ could be in free variation relations. Similar relations were characteristic for so called soft and hard allophones of the phoneme /u/. In general, when reduced, unstressed vowels in both languages moved to the center of the vocalic space replicating the vowel quality reduction pattern common for many other languages.
Morozova et al. (Sun,) studied this question.