On the Origin of the Slavic Aspects: Aorist and Imperfect

This article presents a sketch of the prehistorical development of the Common Slavic preterital imperfect/aorist category. The methods of internal analysis and linguistic geography are applied to mostly well-established data in order to reconstruct major elements of this development, in particular the relative chronology of the main morphological changes, correlations with well-known Common Slavic phonological changes, as well as correlations of regional morphological differences with major phonological isoglosses. The results contribute to our understanding of the development of Common Slavic and its dialectal differentiation in the period of the "Slavic migrations".