Fusion, Fission, and Relevance in Language Change

In Early Greek, ana and ek(s) were still largely independent adverbs. In time, following the normal trend to univerbation ('Today's syntax is tomorrow's morphology'), they became prepositions and -what matters here- preverbs capable of modifying the meaning of a verbal root. As a rule, what took place is univerbation into an unanalyzable verb (fusion). There are, however, some interesting exceptions. The preverb eks- assumed a new shape kse- which preserved morphological transparency, and the conglomerate ksana-(< eks- + ana-) regained independence (fission) as a free adverb: Yesterday's morphology is today's syntax! My paper tries to explain these developments (with parallels in other languages) and to investigate the interplay between form and meaning (constructional diagram-maticity). It is argued that conceptual distance to the semantics of the verb is a determining factor in the behaviour of Greek preverbs. De-univerbation proves to be a very effective means in opposing opacity.