The distinction between imperfective and perfective plays an important role in many verb systems and is commonly signalled by morphological means (rather than being expressed periphrastically). A particularly straightforward case is found in Rendille (East Cushitic; Kenya). Nonstative verbs in Rendille distinguish two basic forms, one which normally ends in -a and one which normally ends in -e, as illustrated by the examples in (1).
(1) Rendille (own data)
‘He writes/is writing/wrote/was writing/will write letters.’
‘He wrote letters.’
The imperfective form in -a is used for reference to the present and the future but also for ongoing and habitual events in the past, as indicated by the translations. The perfective form in -e is basically restricted to single completed events in the past (with some vacillation for past habitual contexts). In most other languages with an imperfective/perfective distinction, this pattern is obscured by interaction with other tense/aspect grams, but the basic opposition between one form (or set of forms) which is used exclusively or almost exclusively for single completed events in the past and another form (or set of forms) which is used for everything else is characteristic of the distinction.
To be interpreted as a perfective, we demand that a form should be the default way of referring to a completed event in the language in question. In many languages, there are forms or constructions that are used of completed events but only if some additional nuance of meaning is intended, for instance if emphasis is put on the result being complete or affecting the object totally. Such strong perfectives (“conclusives” in Dahl (1985) and “completives” in Bybee et al. (1994)) exhibit relatively large variation cross-linguistically. They are often called “perfectives” in grammars but are not counted as such here. The following example is from Rama (Chibchan; Nicaragua), where the suffix –atkul- (derived from a verb meaning ‘finish’) indicates a “strong perfective”:
‘He burned his hand completely.’
We distinguish imperfectives from progressives, with which they partially overlap and which are often seen as a variety of imperfectives. Progressives, as the English is singing or the equivalent Spanish está cantando, have a more restricted domain of use (for instance, they are typically not the primary choice for expressing habitual meaning), which means that they are opposed to non-progressive forms independently of time reference. They are also normally restricted to non-stative verbs. Progressives are frequent diachronic sources of marked imperfectives, and borderline cases admittedly exist.
We also distinguish imperfectives from antipassives, by which we understand processes that operate on transitive constructions to make them less transitive (see Chapter 108). Antipassives, which are particularly frequent in ergative languages, often influence the aspectual character of the sentence, with ranges of meaning similar to those of progressives and imperfectives. The following example is from Bandjalang (Pama-Nyungan; New South Wales, Australia):
(3) Bandjalang (own questionnaire data from M.J. Sharpe)
‘He is writing a letter.’
For this map, only two values have been defined: languages in which there is grammatical marking of the perfective/imperfective distinction (red) and those where there is not (white). “Grammatical marking” here includes both marking by morphological means and by periphrastic constructions.
In most other tense-aspect distinctions, it is possible to arrive at a cross-linguistically consistent choice with respect to overt marking. For the imperfective/perfective distinction, this is not possible. There are languages in which the perfective has no marker and the imperfective has an overt marker, and vice versa, but most often (at least in our sample) no clear marking relations can be identified. (One reason for this is that the distinction is frequently manifested by stem alternations and similar processes.)
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|Grammatical marking of perfective/imperfective distinction||101|
|No grammatical marking of perfective/imperfective distinction||121|
Perfective/imperfective distinctions seem to be less skewed in their geographical distribution than, for instance, past tenses (see Chapter 66). However, we can discern the following tendencies. In a band across southern Eurasia from Europe (excluding most of the northern part) to China (but excluding the Dravidian part of South Asia and all of Southeast Asia), there is fairly consistent marking of perfectivity/imperfectivity. One may see this area as extending into Africa down to the Equator. Interestingly, it overlaps quite considerably with the Eurasian/African past marking area (seen on Map 66A), but lies south of it. Northern Europe outside the Slavic area has very little perfectivity/imperfectivity marking. Other white clusters on the map include large parts of South America and Southeast Asia (see remarks on the latter in Chapter 66).
Even if perhaps not so often formulated as an explicit hypothesis, there seems to be a widespread view of tense and aspect as alternatives to each other – that languages tend to be either “tense languages” or “aspect languages”. If this were the case, we would expect a negative correlation between imperfectives and perfectives on the one hand, and pasts and futures on the other. The data presented here provide no support for such a conclusion. In fact, there are considerably more languages in the sample that have both the aspectual and temporal categories, or neither of the alternatives, than have one only. It is plausible that there is rather a positive correlation between all the categories under discussion and the general morphological complexity of the verb.