Grammatical conjugation

In linguistics, conjugation is the creation of derived forms of a verb from its principal parts by inflection. For instance, the verb break can be conjugated to form the words break, breaks, and broke. While English has a relatively simple conjugation, other languages such as French and Arabic or Spanish are more complex, with each verb having dozens of conjugated forms. Some languages such as Georgian and Basque have highly complex conjugation systems with hundreds of possible conjugations for every verb.
Verbs may inflect for grammatical categories such as person, number, gender, case, tense, aspect, mood, voice, possession, definiteness, politeness, causativity, clusivity, interrogatives, transitivity, valency, polarity, telicity, volition, mirativity, evidentiality, animacy, associativity, pluractionality, and reciprocity. Verbs may also be affected by agreement, polypersonal agreement, incorporation, noun class, noun classifiers, and verb classifiers. Agglutinative and polysynthetic languages tend to have the most complex conjugations, although some fusional languages such as Archi can also have extremely complex conjugation. Typically the principal parts are the root and/or several modifications of it. All the different forms of the same verb constitute a lexeme, and the canonical form of the verb that is conventionally used to represent that lexeme is called a lemma.
The term conjugation is applied only to the inflection of verbs, and not of other parts of speech. It is also generally restricted to denoting the formation of finite forms of a verb – these may be referred to as conjugated forms, as opposed to non-finite forms, such as an infinitive, gerund, or participle which respectively comprise their own grammatical categories.
Conjugation is also the traditional term for a group of verbs that share a similar conjugation pattern in a particular language. For example, Latin is said to have four conjugations of verbs. This means that any regular Latin verb can be conjugated in any person, number, tense, mood, and voice by knowing which of the four conjugation groups it belongs to, and its principal parts. A verb that does not follow all of the standard conjugation patterns of the language is said to be an irregular verb. The system of all conjugated variants of a particular verb or class of verbs is called a verb paradigm; this may be presented in the form of a conjugation table.

Verbal agreement

Verbal agreement, or concord, is a morpho-syntactic construct in which properties of the subject and/or objects of a verb are indicated by the verb form. Verbs are then said to agree with their subjects.
Many English verbs exhibit subject agreement of the following sort: whereas I go, you go, we go, they go are all grammatical in standard English, he go is not. Instead, a special form of the verb to go has to be used to produce he goes. On the other hand I goes, you goes etc. are not grammatical in standard English. A few English verbs have no special forms that indicate subject agreement, and the verb to be has an additional form am that can only be used with the pronoun I as the subject.
Verbs in written French exhibit more intensive agreement morphology than English verbs: je suis, tu es, elle est, nous sommes, vous êtes, ils sont. Historically, English used to have a similar verbal paradigm. Some historic verb forms are used by Shakespeare as slightly archaic or more formal variants of the modern forms.
Some languages with verbal agreement can leave certain subjects implicit when the subject is fully determined by the verb form. In Spanish, for instance, subject pronouns do not need to be explicitly present, but in French, its close relative, they are obligatory. The Spanish equivalent to the French je suis can be simply soy. The pronoun yo in the explicit form yo soy is used only for emphasis or to clear ambiguity in complex texts.
Some languages have a richer agreement system in which verbs agree also with some or all of their objects. Ubykh exhibits verbal agreement for the subject, direct object, indirect object, benefaction and ablative objects.
Basque can show agreement not only for subject, direct object and indirect object but it also can exhibit agreement for the listener as the implicit benefactor: autoa ekarri digute means "they brought us the car", but autoa ekarri ziguten means "they brought us the car".
Languages with a rich agreement morphology facilitate relatively free word order without leading to increased ambiguity. The canonical word order in Basque is subject–object–verb, but all permutations of subject, verb and object are permitted.

Nonverbal person agreement

In some languages, predicative adjectives and copular complements receive a form of person agreement that is distinct from that used on ordinary predicative verbs. Although that is a form of conjugation in that it refers back to the person of the subject, it is not "verbal" because it always derives from pronouns that have become clitic to the nouns to which they refer. An example of nonverbal person agreement, along with contrasting verbal conjugation, can be found from Beja :

wun.tu.wi, “you are big”
hadá.b.wa, “you are a sheik”
e.n.fór, “he flees”

Another example can be found from Ket:

fèmba.di, “I am a Tungus”
dɨ.fen, “I am standing”

In Turkic, and a few Uralic and Australian Aboriginal languages, predicative adjectives and copular complements take affixes that are identical to those used on predicative verbs, but their negation is different. For example, in Turkish:

koş.u.yor.sun “you are running”
çavuş.sun “you are a sergeant”

Under negation, that becomes :

koş.mu.yor.sun “you are not running”
çavuş değil.sin “you are not a sergeant”

Therefore, the person agreement affixes used with predicative adjectives and nominals in Turkic languages are considered to be nonverbal in character. In some analyses, they are viewed as a form of verbal takeover by a copular strategy.

Factors that affect conjugation

These common grammatical categories affect how verbs can be conjugated:

Finite verb forms:
*Grammatical person
*Grammatical number
*Grammatical gender
*Grammatical tense
*Grammatical aspect
*Grammatical mood
*Grammatical voice
Non-finite verb forms.

Here are other factors that may affect conjugation:

Degree of formality
Clusivity
Transitivity
Valency
Examples

usually inflect verbs for several grammatical categories in complex paradigms, although some, like English, have simplified verb conjugation to a large extent. Below is the conjugation of the verb to be in the present tense, in English, German, Yiddish, Dutch, Afrikaans, Icelandic, Faroese, Swedish, Norwegian, Latvian, Bulgarian, Serbo-Croatian, Polish, Slovenian, Macedonian, Urdu or Hindi, Bengali, Persian, Latin, French, Italian, Spanish, Portuguese, Russian, Albanian, Armenian, Irish, Ukrainian, Ancient Attic Greek and Modern Greek. This is usually the most irregular verb. The similarities in corresponding verb forms may be noticed. Some of the conjugations may be disused, like the English thou-form, or have additional meanings, like the English you-form, which can also stand for second person singular or be impersonal.

Conjugation classes

Pama-Nyungan languages

One common feature of Pama–Nyungan languages, the largest family of Australian Aboriginal languages, is the notion of conjugation classes, which are a set of groups into which each lexical verb falls. They determine how a verb is conjugated for Tense–aspect–mood. The classes can but do not universally correspond to the transitivity or valency of the verb in question. Generally, of the two to six conjugation classes in a Pama-Nyungan language, two classes are open with a large membership and allow for new coinages, and the remainder are closed and of limited membership.

Wati

In Wati languages, verbs generally fall into four classes:

l class
∅ class
n class
ng class

They are labelled by using common morphological components of verb endings in each respective class in infinitival forms. In the Wanman language these each correspond to la, ya, rra, and wa verbs respectively.
Class Past Present Future Imperative Past Continuous Habitual
LA -rna -npa/-rni -nku -la -rninya la
LA waka-rna waka-rni waka-nku waka-la waka-rninya waka-la
LA speared is spearing will spear spear it! used to spear spears
YA -nya -manyi -ku -∅/-ya -minya -∅/-ya
YA wanti-nya wanti-manyi wanti-ku wanti-ya wanti-minya wanti-ya
YA stayed is staying will stay stay! used to stay stays
RRA -na -npa -nku -rra -ninya -rra
RRA ya-na ya-npa ya-nku ya-rra ya-ninya ya-rra
RRA went is going will go go! used to go goes
WA -nya -nganyi -ngku -wa -nganyinya -wa
WA pi-nya pi-nganyi pi-ngku pi-wa pi-nganyinya pi-wa
WA hit is hitting will hit hit it! used to hit hits

See also a similar table of verb classes and conjugations in Pitjantjatjara, a Wati language wherein the correlating verb classes are presented below also by their imperative verbal endings -la, -∅, -ra and -wa respectively
Class Past Present Future Imperative Past Continuous Habitual
LA -nu -ni -lku -la -ningi -lpai
LA kati-nu kati-ni kati-leu kati-la kati-ningi kati-lpai
LA took is taking will take take it! used to take takes
∅ -ngu -nyi -ku -∅ -ngi -pai
∅ tawa-ngu tawa-nyi tawa-ku tawa-∅ tawa-ngi tawa-pai
∅ dug is digging will dig dig! used to dig digs
RA -nu -nangi -nkuku -ra -nangi -nkupai
RA a-nu a-nangi a-nkuku a-ra a-nangi a-nkupai
RA went is going will go go! used to go goes
WA -ngu -nganyi -nguku -wa -ngangi -ngkupai
WA pu-ngu pu-nganyi pu-nguku pu-wa pu-ngangi pu-ngkupai
WA hit is hitting will hit hit it! used to hit hits

Class	Past	Present	Future	Imperative	Past Continuous	Habitual
LA	-rna	-npa/-rni	-nku	-la	-rninya	la
LA	waka-rna	waka-rni	waka-nku	waka-la	waka-rninya	waka-la
LA	speared	is spearing	will spear	spear it!	used to spear	spears
YA	-nya	-manyi	-ku	-∅/-ya	-minya	-∅/-ya
YA	wanti-nya	wanti-manyi	wanti-ku	wanti-ya	wanti-minya	wanti-ya
YA	stayed	is staying	will stay	stay!	used to stay	stays
RRA	-na	-npa	-nku	-rra	-ninya	-rra
RRA	ya-na	ya-npa	ya-nku	ya-rra	ya-ninya	ya-rra
RRA	went	is going	will go	go!	used to go	goes
WA	-nya	-nganyi	-ngku	-wa	-nganyinya	-wa
WA	pi-nya	pi-nganyi	pi-ngku	pi-wa	pi-nganyinya	pi-wa
WA	hit	is hitting	will hit	hit it!	used to hit	hits