[…] the attendant circumstances which present themselves for inclusion in verbal expression, and in one or another language find expression, are simply numberless […] To us, the element of time is the conspicuous and pressing one; the denoting of an action appears almost to require an implication of tense-relation. Yet many languages do not regard this element as calling for inclusion in the fundamental structure of the verb rather than others; and they leave it to be inferred from the connection, or intimated by external means, particles, auxiliaries, as we on our part treat other elements which they weave into the verbal structure.
- Whitney (1875), a pag.219