It is difficult to isolate precise meanings in the domain of tense and aspect because notions like perfectivity subsume distinctions such as punctuality, completedness, resultativity and stativity. […]. Thus, accomplishment is one aspect of perfectivity. There is also an inevitable overlap between tense and aspect since pastness and perfectivity overlap. Events that are completed, ie perfective, are by definition past. The interpretation of perfective aspect depends on the type of event. Perfective aspect implies completion for perfective events and termination for imperfective events.
- Romaine (1988), a pag.283

One could also interpret some of the evidence from creoles as being consistent with the hypothesis that perfectivity or completion rather than punctuality is the first distinction to be grammaticalized.
- Romaine (1988), a pag.284