The article aims at the explanation of some distributional peculiarities of two high unrounded vowels [i] and [È] in Russian. More generally, it looks at some phonotactic constraints of Russian vowels which are directly related to a broader topic of palatalization and vowel reduction in this language. Although the discussion in this paper concerns only a tiny section of Russian phonology, which is the distribution of high unrounded vowels, it is necessary to introduce several facts from Russian phonology, such as palatalization, velarization, stress and vowel reduction. They, at first sight, may look pretty much irrelevant to the main topic of the paper but, as it will become evident, are closely related and actually indispensable to the understanding of vowel distribution including the two high unrounded vowels in Russian.
The paper investigates the interdependence between the perceptual identification of the vocalic quality of six isolated Polish vowels traditionally defined by the spectral envelope and the fundamental frequency F0. The stimuli used in the listening experiments were natural female and male voices, which were modified by changing the F0 values in the ±1 octave range. The results were then compared with the outcome of the experiments on fully synthetic voices. Despite the differences in the generation of the investigated stimuli and their technical quality, consistent results were obtained. They confirmed the findings that in the perceptual identification of vowels of key importance is not only the position of the formants on the F1 × F2 plane but also their relationship to F0, the connection between the formants and the harmonics and other factors. The paper presents, in quantitative terms, all possible kinds of perceptual shifts of Polish vowels from one phonetic category to another in the function of voice pitch. An additional perceptual experiment was also conducted to check a broader range of F0 changes and their impact on the identification of vowels in CVC (consonant, vowel, consonant) structures. A mismatch between the formants and the glottal tone value can lead to a change in phonetic category.