This study deals with the cross-linguistic interpretation of aspect and tense in natural languages which have superficially disparate morphological structure. It is argued that in Yao, Chea (Bantu languages) and English, where aspect for instance, is not as systematically grarnmaticalized as it is in Slavic, the interpretation of aspect and tense must be one which construes them as theoretical (conceptual) categories. We assume essentially that both aspect and tense are characterized by temporal primitives which are often though riot invariably, denoted by morphological markers. "Verbal aspect" in Slavic for example, is effectively defined by the temporal stretch encoded in (or signalled by) a productive system of afuixal marking. The temporal stretch is characteristically completive, inceptive, resumptive, durative, continuative, punctual, iterative etc. These aspectual time schemata have affinities with those assumed by philosophers and linguists like Vendler (1957), Kenny (1963), Dowty (1977, 1979) and others for the classification of verbs and verb phrases. These in turn are similar to the time schemata encoded by such categories as adverbials and noun phrases. Accordingly, though Yao, Chea and English might not mark aspect morphologically in the manner common in Slavic, the specification of aspect is assured by the semantic content of VPs, ADVs etc., thus facilitating a cross-linguistic treatment of the category. Correspondingly, "tense", which is a deictic category and is largely morphologized in Yao and Chea is also best understood when we examine the temporal structure of whole utterances. We take tense to be a category orthogonal to aspectual concepts like continuity, habituality, inception, completion etc. and which specifies how these are related to each other, in terms of whether or not they are anterior or posterior to or simultaneous with the speech time of utterances in question (Cf. Reichenbach, 19147; and followers). Traditional and model-theoretic treatments of these concepts have inadequacies which manifest themselves in the form of such problems as the "imperfective paradOx" (Cf. Dowty, ibid), the "gaps problem" (Cf. Bennett, 1981), the problem of the lack of difference in truth conditions between the "simple past" and "perfect" utterances when it is clear that some (intuitively semantic) difference between them exists etc. It is suggested that these issues be resolved within pregmatics of the Gricean (1968, 1975 etc) type as recently extended by Sperber & Wilson (1982, forthcoming). On the interpretation of aspect and tense in Yao, Che'a and English then, this study takes the view that two factors are operative: semantic factors exemplified by the knowledge (or identification) of the time schemata encoded in morphological markers, words and constructions and the truth-conditional processing of the propositions thus expressed on the one hand, and pragmatic factors of their use (e.g. the "principle of relevance" of Sperber & Wilson, ibid.) which determine the choice of the appropriate construal of those utterances which are especially temporally indeterminate on the other.