The argument structure of verbs is pretty uniform across languages. Thus, verbs of `falling’ involve a Theme and an optional Causer and verbs of `working’ an Agent. Aspect is relevant to that uniformity as well since the former verbs will be telic and the latter durative. Stative verbs form a third main class. I first show that, when (spoken/written) languages change, the basic argument structure and aspect don’t change for most unaccusatives and unergatives. There are, however, systematic reports (e.g. Rosen 1984; Keller & Sorace 2003; Randall et al 2004) that certain verbs are unergative in one language and unaccusative in another and that verbs alternate between different aspects (e.g. Levin & Rappaport Hovav 2014). I examine a few verbs diachronically that are ambiguous in the Keller & Sorace work, i.e. verbs of continuation and of controlled motional process, and conclude that a more fine-grained system is helpful.