A verb is a word used primarily to indicate a type of action, such as to fly or to wish, though it may also be used to indicate a general state of existence, such as to live. There is also a special type of verb, known as a copula or linking verb, which helps to describe the subject of the sentence, rather than describing an action. The primary example of this in English is the verb to be which is usually used in the role of linking verb. A verb is one of the basic building blocks of a sentence in most languages, with most grammatical sentences requiring at least one noun acting as a subject, and one verb to indicate an action.
Verbs can be inflected, which means the verb is changed in some way to indicate something about the sentence the verb is a part of. A verb may be inflected to describe virtually anything. Some common inflections are listed below.
Tense indicates the time in which the verb takes place. In English this usually differentiates between the past, the present, and the future. For example, using the same nouns and the same verb, we can inflect the verb in the following sentence to describe three states of time: The woman sat on the chair or The woman sits on the chair or The woman will sit on the chair. Some languages may also distinguish between distant past, recent past and present; between past, present and future, or far future, and so on. Some may make no distinction through inflection, instead using adverbs or auxiliaries -- for instance, English doesn't actually inflect between present and future tense, we use a modifier, as in the sits/will sit example.
Aspect describes something about the internalized nature of the verb. This can distinguish between progressive and non-progressive -- for instance, we could inflect the sentence I pick up the bucket to mean you pick up the bucket eternally, or just at a set time every day, or just once, or as a prelude to some further action, and so on. It can distinguish between a static and dynamic state -- a particular as opposed to a changing one -- such as in Arabic rukubun, in its static state meaning 'ride', and in its dynamic state meaning 'to mount'.
Mood gives the verb's relationship to intent or reality. English doesn't use many moods, but it does use the indicative, describing fact and opinion as in Ursula sat down; the imperative, describing command or prohibition as in Ursula, sit down; and the subjunctive, which is pretty open-ended, including theoretical events, opinions, emotions, or requests, as in Jim suggested Ursula sit down. Other languages make use of a negative mood, instead of using a distinct word, such as not, which would be something like Ursula not-sit down; and some have an opative mood, expressing hopes or desires, as in Classical Greek would that Ursula would sit down.
Object helps to distinguish between the transitive, intransitive, and reflexive forms of a verb. A transitive verb acts upon the object of the sentence, an intransitive verb simply acts, and a reflexive verb acts on the subject. In English, most verbs have at least a transitive and an intransitive form, and the word is usually the same.
Voice shows where the verb is focused. The most basic distinction of voice is between active, subject focused sentences such as I cooked the broccoli, and passive, object focused sentences such as The broccoli was cooked by me. As you can see, in English, voice is very rarely inflected, and instead indicated by word order and prepositions. Voice can also take a 'middle' form, as in Sanskrit -- in English, our best example is the inchoative, a verb that seems active but demonstrates a passive action, such as The broccoli cooked on the pan.
Other types of verb inflection used in various languages include showing relationships, such as inflecting verbs in Japanese to indicate levels of respect for a person; levels of certainty in a given statement by the speaker; and conditional clauses such as If I run.
_________________
