??(??)?? ????????????, ???????????? ???? '?? ????'???? ??, ?? ?????????? ???????????????? ?????? ???? ????????.  If a grammatical principle that may be additional to ????is usually a vowel ??and there is no other possibility apart from a vowel ??then that grammatical theory can not be added to ??????? ?? ?? ?????? ?? ?? ????? ??? ?? ?? - ?????? ?