??????????? ????????????? ??? ???????? ? ?????????? ??? ?? ??? ?? ???????? ??? ????? ????? ??? ?? ??????? ??? ??? ?? ???????? ???? ??????? ??? ???? ????????simplification on the procedure of vowels and diphthongs: loss of vowel length difference, monophthongisation of most diphthongs and several other steps in a chain change of vowels toward /i/ (i