PHONEMES /†/ И /w/ IN SOUTH RUSSIAN DIALECTS (INSTRUMENTAL PHONETIC STUDY)
The paper shows that a tone glide which begins with a high vowel and changes to a mid vowel (with a gradual increase in intensity) should be regarded as a characteristic feature of the phonemes /†/ and /w/. A vowel system which consists of seven phonemes can only function with diphthongs [i.. e] and [uo], which are realised as the phonemes /†/ and /w/ respectively. These diphthongs manifest a completely parallel structure. Firstly, it explains the nature of the diphthongal /†/ in South Russian dialects; secondly, it supports the view that the phoneme /w/ appears to be a correlate of the phoneme /†/, which is a result of the trend towards the symmetrisation of the Old Russian language phonological system. This basic similarity between the allophones /†/ and /w/ is only found in dialect systems with a phoneme set containing seven vowel phonemes. The tendency for diphthongs to turn into simple vowels primarily affects the diphthong [i. e] and only secondarily the diphthong [u. o]. The process of monophthongisation leads to the development of asymmetrical vowel systems which are characterised by a statistically significant dominance of the diphthong [i.. e] over the diphthong [uo].