Perfective and Imperfective Aspect

Definition

The aspect in grammar refers to how an action, state or event is viewed in relation to time. The main distinction is made between the perfective aspect, which emphasizes the completed or finished action, and the imperfective aspect, which focuses on the process or duration of the action. While other languages may use inflected verb forms to indicate aspect, English uses a combination of particles, verbs, verb phrases, and lexical clues to determine the aspect of an action.

What is the perfective aspect?

The perfective aspect emphasizes actions, states, or events as a whole, viewing them from an external perspective as finished and distinct occurrences.

The perfective aspect is encountered in all of the tenses—past, present, and future—but it is easiest to illustrate in the past. For example:

• “I went to the supermarket yesterday.” (past simple tense)
• “She sang in the choir.” (past simple tense)
• “We had eaten already.” (past perfect tense)

All of the examples above present the action as a finished occurrence in the past, providing no indication of the frequency or duration of the actions.

As mentioned, the perfective aspect also occurs in other tenses. For example:

• “I have a dog.” (present simple tense)
• “She’ll be there soon.” (future simple tense)
• “They will have finished by then.” (future perfect tense)

What is the imperfective aspect?

The imperfective aspect, on the other hand, is used when we focus on the internal structures of an action, state, or event as it relates to time, such as being continuous or habitual (repeating). Again, this has nothing to do with when the event occurs, and, as with the perfective, there is no separate verb form in English for the imperfective aspect.
Instead, it is expressed through different grammatical structures, which change depending on what we are saying about the temporal structure of the action.

We sometimes classify these structures as the continuous aspect and the habitual aspect, both of which are subclasses of the imperfective.

Continuous Aspect

The continuous aspect, also known as the progressive aspect, is a subset of the imperfective aspect, which emphasizes the continuous nature of the verb, showing that the action is ongoing or unfinished over a specific period of time. It does not specify the duration of the action or how frequently it happens, only that it is happening at the time of speaking or another event. It can be used with the past, present, and future tenses, and it is usually conveyed using a form of the verb be + the present participle. For example:

Past

• “I was talking to my mother when you called.”
• “They had been living here for a long time when they moved.”

Present

• “I’m cooking dinner at the moment, so I’ll have to call you back.”
• “She’s been playing outside with her friends all day.”

Future

• “He’ll be sleeping by 10 o’clock, hopefully.”
• “Next month we’ll have been living in Oakland for 10 years.”

It should be noted that stative verbs do not normally occur using the be + present participle structure. For example, you could not say “I am knowing John a long time” or “She is appearing unwell.”

Other constructions

There is disagreement over whether structures using be + the present participle are the only structures that depict the continuous aspect. It is often argued, for example, that the past simple often conveys the continuous aspect. For example:

• “I stayed up all night.”
• “We were outside for hours.”

Others would argue that since it is the additional information in the examples above (all night and for hours) that gives the continuous aspect to the sentence as a whole, the verb phrases themselves should not be considered to convey continuous aspect.

Habitual Aspect

The habitual aspect, like the continuous aspect, is also a subclass of the imperfective aspect. It is used when an action occurs repetitively and (usually) predictably. English only has two marked ways of expressing habitual aspect: would + base form of the verb (the infinitive without to) and used to + base form of the verb. When we use these structures, we imply that the action occurred habitually in the past, but does not anymore. For example:

• “When I was young I used to walk to school.”
• “When I was young I would walk to school.”

Although the meaning in the two examples above is the same, used to and would are not always directly interchangeable. For example, used to, standing alone, conveys habitual aspect, but would doesn’t. Observe what happens if we remove the time marker when I was young:

• “I used to walk to school.”
• “I would walk to school.”

When we remove when I was young from the examples, the example using used to retains its habitual aspect, but the example with would doesn’t. Since would can also be used in conditional constructions, we need to include a time marker to clarify when it is being used for the habitual past.

In addition, while used to can be used with both action verbs and stative verbs, would can only be used with action verbs. For example:

• “When I was young, I used to love movies.” (correct)
• “When I was young, I would love movies.” (incorrect)

Other constructions

Although used to + base form and would + base form are the only structures that explicitly mark habitual aspect, we often use other verb tenses to convey it as well. For example, we often use the present simple tense to indicate habitual actions, as in:

• “I go to school every day.”
• “She attends karate class on Sundays.”
• “They work six days a week.”

However, other verb tenses can be used with an implied habitual aspect. For example:

• “I walked to school every day for 10 years.” (past simple tense)
• “I had lived in the same town my whole life before I decided to move to Tokyo.” (past perfect tense)
• “She has eaten the same sandwich for lunch for as long as I’ve known her.” (present perfect tense)

When the habitual aspect is unmarked, as above, it is often accompanied by a time marker that clarifies how often the action occurs, such as every day, on Sundays, six days a week, etc.

Future habits

English does not have an explicit habitual aspect marker for the future either. Most often, we use the future simple tense along with a time marker to indicate habit. For example:

• “I will work extra shifts every evening until I save enough money.”
• “I will go for a run every day after school this year.
• “We will eat fruit and cereal every morning next month.”

As with the alternate constructions of the continuous aspect, there is disagreement over whether unmarked verb forms can be considered to express habitual aspect, since it may simply be the additional information in the sentence that expresses the habitual meaning, rather than the verb phrases themselves.