This paper is concerned with a specific proposal of a formalism for studying tenses, namely Hans Reichenbach's "three-point structure" [14]. That proposal explicitly claims to be based on Jespersen's ideas on time and tense in [10]. The main goal is to examine the relationship between this logic and its underlying linguistic assumptions, with a particular view to A. N. Prior's tense logic. We bring forth a historical as well as a systematical result. The historical result consists in revealing certain prevalent misunderstandings concerning Reichenbach's linguistic background in Jespersen's work. The systematical result consists in determining a specific relation between some well-established linguistic temporal categories and tense logic. Thus the following study may serve to show how a careful examination of underlying linguistic assumptions may bear on the development of logic, and conversely, how logical observations can be fruitfully employed in the study of language.