Goals and sources are aspectually equal: Evidence from Czech and Russian prefixes

With respect to their semantic and syntactic behaviour, Slavic verbal prefixes fall into at least two groups. Internal prefixes are locative Ps that constitute a result state subevent, and events described by internally prefixed verbs are telic. External prefixes, on the other hand, are generated outside the VP and function as adverbial modifiers (Czech) or perfectivity markers (Russian). An apparent counter-example to this distinction comes from Czech, which shows an asymmetry between source and goal prefixes: only the former but not the latter are compatible with measure phrases. On grounds of such examples, Filip (2003) argues that only goal prefixes derive telic predicates, whereas source prefixes form atelic predicates. However, both prefixes display internal diagnostics and VPs containing either behave like telic predicates with respect to telicity tests. I propose an alternative account for the asymmetry, claiming that it results from different monotonicity properties of the particular result states. With source Ps the result state is topologically open and thus compatible with further modification by measure phrases, whereas a result state with a closed topology (with goal Ps) is not.