[...] certain languages have developed the idea of 'aspect' (momentaneous, durative, continuative, inceptive, cessative, durative-inceptive, iterative, momentaneous-iterative, durative-iterative, resultative, and still others).
- Sapir (1921), a pag.107

A term borrowed from Slavic grammar. It indicates the lapse of action, its nature from the standpoint of continuity. Our 'cry' is indefinite as to aspect, 'be crying' is durative, 'cry out' is momentaneous, 'burst into tears' is inceptive, 'keep crying' is continuative, 'start in crying' is durative-inceptive, 'cry now and again' is iterative, 'cry out every now and then' [...] is momentaneous-iterative.
- Sapir (1921), a pag.108

[...] aspect is expressed in English by all kinds of idiomatic turns rather than by a consistently worked out set of grammatical forms. In many languages aspect is of far greater formal significance than tense [...]
- Sapir (1921), a pag.108