The imperfective (abbreviated or more ambiguously ) is a grammatical aspect used to describe ongoing, habitual, repeated, or similar semantic roles, whether that situation occurs in the past, present, or future. Although many languages have a general imperfective, others have distinct aspects for one or more of its various roles, such as progressive, habitual, and iterative aspects. The imperfective contrasts with the perfective aspect, which is used to describe actions viewed as a complete whole.
English is an example of a language with no general imperfective. The English progressive is used to describe ongoing events, but can still be used in past tense, such as "The rain was beating down". Habitual situations do not have their own verb form (in most dialects), but the construction "used to" conveys past habitual action, as in I used to ski. Unlike in languages with a general imperfective, in English the simple past tense can be used for situations presented as ongoing, such as The rain beat down continuously through the night.
A contrast between the progressive and imperfective is seen with stative verbs. In English, stative verbs, such as know, do not use the progressive (*I was knowing French is ungrammatical), while in languages with an imperfective (for instance, French), stative verbs frequently appear in the imperfective.
African American Vernacular English does have an imperfective aspect for present tense formed by adding "be" before the present continuous of a verb, such as "he be working", or "they be eating".
Verbs in Hindi-Urdu (Hindustani) have their grammatical aspects overtly marked. Periphrastic Hindi-Urdu verb forms (participle verb forms) consist of two elements, the first of these two elements is the aspect marker and the second element (the copula) is the common tense-mood marker. There are two independent imperfective aspects in Hindi-Urdu: Habitual Aspect, and Progressive Aspect. These two aspects are formed from their participle forms being used with the copula verb of Hindi which is होना honā (to be).