Verb Aspect and Prototype Theory

Verb aspect is a phenomenon of widespread occurrence and considerable variability in the world’s languages (see, e.g., Comrie, 1976; Dahl, 1985). In English its main manifestation consists of two grammatical oppositions, that between the simple and continuous forms of the verb, as in I eat vs I am eating, and that between the simple and perfect forms, as in I eat vs I have eaten. English allows the perfect form to combine with the continuous, to produce I have been eating. The forms illustrated here are in the present tense. In addition, each of them may occur in the past: I ate/was eating/had eaten/had been eating. Although both tense and aspect have to do with temporal features of meaning, aspect is normally regarded as quite separate from tense: where tense is concerned with the location of a state or event in time, aspect is concerned more with its temporal ‘shape’, either intrinsically or from a particular point of view. What makes these grammatical features aspectual is the fact that they make a particular kind of contribution to the meanings of the sentences in which they occur. An adequate theoretical account of aspectual phenomena should characterise the nature of these contributions. Aspect has, in fact, been the subject of much study in linguistics, both conventional and computational, and a loose consensus seems to have emerged that an adequate account of it should look somewhat as follows. A verb phrase describes a ‘situation’ or ‘eventuality’ (the terminology is notoriously slippery) of a particular type, and its grammatical aspect then modifies this by converting it into a different type. This gives us two aspectual notions, primary aspect, which concerns the classification of the situation-type denoted by the bare (uninflected) verb phrase, and secondary aspect, which refers to the transformations of situation-type resulting from the grammatical modifications of the verb1. This distinction is primarily a semantic one, but it tends to be reflected syntactically too, and in various different ways. In fact, the distinction itself is sufficiently unclear that the means of syntactic expression may be the best guide we have to drawing the boundary satisfactorily. Thus when aspect is expressed lexically, as with the distinction between travel (durative—i.e., referring to something which takes time) and arrive (punctual—i.e., referring to an instantaneous event), or contextually, as with eat a boiled egg (telic—i.e., with a built-in termination point) and eat scrambled egg (atelic— i.e., with no built-in termination), we call it inherent or primary aspect, but when it is expressed morphologically, as with eat vs be eating (indicating an action in progress) vs have eaten (indicating a completed action), we call it imposed or secondary aspect. But these syntactic distinctions are