In linguistics, grammatical conjugation is the creation of derived forms of a verb from the word root by inflection (regular alteration according to rules of grammar). Conjugation may be affected by person, number, gender, tense, mood, voice, grammatical aspect, or other language-specific factors. When a verb is used to function as the action done by a subject, the verb must be conjugated in most languages. Usually a mostly unconjugated form also exists, called the infinitive. A table giving all the conjugated variants of a verb in a grammar of some language is called a conjugation table.

A second use of the term is the grouping of all the verbs that are conjugated similarly in a particular language into conjugations. This is the sense in which teachers say that Latin has four conjugations of verbs. This categorisation tells us that we can conjugate any regular Latin verb to any person, number, tense, mood, and voice if we know which conjugation group it belongs to and some key forms called principal parts. (Latin does not conjugate for gender or aspect.)

Examples of conjugation

Conjugation is very extensive in most Indo-European languages. Here is a sample conjugation of the English verb to be and its Latin, French, German, Spanish, Portuguese, and Swedish equivalents—esse, être, sein, ser, ser, and vara, respectively. Notice the similarities between English, German, and Swedish on the one hand and French, Spanish, Portuguese and Latin on the other; notice also that, where the infinitive is concerned, only English and Swedish are very much divergent from the rest of the major European languages, all of which lends important clues as to the philology of English.

Related topics

The grammatical conjugation of an irregular verb forms a model for a genre of joke called the self-serving conjugation. This satirizes the fashion in which violations of the Categorical Imperative may be cloaked in verbal obfuscation. For example: I delegate effectively, you play politics, he is in violation of his service-level agreement.