Imperfective Aspect - Imperfective and Perfective

Imperfective and Perfective

The opposite aspect is the perfective (in Ancient Greek, generally called the aorist), which views a situation as a simple whole. (This is not the same as the perfect.) Unlike most other tense–aspect category oppositions, it is typical for a language not to choose either perfective or imperfective as being generally marked and the other as being generally unmarked.

In narrative, one of the uses of the imperfective is to set the background scene ("It was midnight. The room was dark. The rain was beating down. Water was streaming in through a broken window. A gun lay on the table."), with the perfective describing foregrounded actions within that scene ("Suddenly, a man burst into the room, ran over to the table, and grabbed the gun.").

English does not have these aspects. However, the background-action contrast provides a decent approximation in English:

"John was reading when I entered."

Here 'entered' presents "the totality of the situation referred to : the whole of the situation is presented as a single unanalysable whole, with beginning, middle, and end all rolled into one; no attempt is made to divide this situation up into the various individual phases that make up the action of entry." This is the essence of the perfective aspect: An event presented as an unanalyzed whole.

'Was reading', however, is different. Besides being the background to 'entered', the form 'reading' presents "an internal portion of John's reading, no explicit reference to the beginning or to the end of his reading." This is the essence of the imperfective aspect. Or, to continue the quotation, "the perfective looks at the situation from the outside, without necessarily distinguishing any of the internal structure of the situation, whereas the imperfective looks at the situation from inside, and as such is crucially concerned with the internal structure of the situation, since it can both look backwards towards the start of the situation, and look forwards to the end of the situation, and indeed it is equally appropriate if the situation is one that lasts through all time, without any beginning and without any end."

This is why, within the past tense, perfective verbs are typically translated into English as simple past, like 'entered', whereas imperfective verbs are typically translated as 'was reading', 'used to read', and the like. (In English, it is easiest to illustrate aspect in the past tense. However, any tense is possible: Present "John is reading as I enter", future "John will be reading when I enter", etc.: In each tense, the aspectual distinction is the same.)

This aspectual distinction is not inherent to the events themselves, but is decided by how the speaker views them or wishes to present them. The very same event may be described as perfective in one clause, and then imperfective in the next. For example,

"John read that book yesterday; while he was reading it, the postman came,"

where the two forms of 'to read' refer to the same thing. In 'John read that book yesterday', however, John's reading is presented as a complete event, without further subdivision into successive temporal phases; while in 'while he was reading it', this event is opened up, so that the speaker is now in the middle of the situation of John's reading, as it is in the middle of this reading that the postman arrives.

The perfective and imperfective need not occur together in the same utterance; indeed they more often do not. However, it is difficult to describe them in English without an explicit contrast like "John was reading when I entered."