Ablaut and transitive softening in the Russian verb

Transitive softening in Russian is a type of consonant mutation resulting from an underlying [CjV] cluster. There exist two closed classes verbs where it occurs the present tense absence clear source for glide: five with thematic suffix ‑o‑, which can be illustrated by verb kolótʲ ‘to stab’, and some 100 ‑a‑, pisátʲ write’. To explain how [o] [a] end up as glides, I propose that vowels question change into their front counterparts result same process responsible stem ablaut molótʲ grind’ (1sg: melʲú). argue hypothesis apply to well stems makes possible account another exhibiting unexpected behavior (revétʲ bellow’). Since latter part argument introduces ablauts involving more than one feature, remainder paper dedicated discussion multiple feature changes should formalized.