This presentation examines the problematic and inconsistent handling of the early Slavic vowel systems with respect to their labeling and theoretical status, their notational representation and which sounds are attributable to various stages of phonological development. Following Jouko Lindstedt (1991) and Georg Holzer (passim), it is argued that the traditional, eleven-vowel "Common Slavic" model cannot properly represent a common ancestral stage from which the individuated Slavic vowel systems developed, but rather corresponds to the vowel system of Old Church Slavonic, from which it is ultimately derived.
It may find validity as a Common Slavic model only insofar as it's elements each stand for a given set of (yet) functionally isomorphic post-Proto-Slavic reflexes of an earlier Proto-Slavic phoneme.