The word copula originates from the Latin noun for a "link or tie" that connects two different things. In linguistics, a copula is a word that is used to link the subject of a sentence with a predicate (a subject complement or an adverbial). Though it might not itself express any action or condition, it serves to equate (or associate) the subject with the predicate.

A copula is sometimes (though not always) a verb or a verb-like part of speech. In English primary education grammar courses, a copula is often called a linking verb.

The term is generally used to refer to the main copular verb in the language: in the case of English, this is "to be". It can also be used to refer to all such verbs in the language: in that case, English copulas include "to be", "to become", "to get", "to feel", and "to seem". Other verbs have secondary uses as copulative verbs, as fall in "The zebra fell victim to the lion."

For a complete list see: List of English copulas.

The copula in English

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Use

We can identify several sub-uses of the copula:

• Identity: "I only want to be myself." "When the area behind the dam fills, it will be a lake." "The Morning Star is the Evening Star." "Boys will be boys." "I yam what I yam" (Popeye).
• Class membership. To belong to a set or class: "She could be married." "Dogs are canines." "Moscow is a large city." Depending on one's point of view, all other uses can be considered derivatives of this use, including the following non-copular uses in English, as they all express a subset relationship.
• Predication (property and relation attribution): "It hurts to be blue." "Will that house be big enough?" "The hen is next to the cockerel." "I am confused." Such attributes may also relate to temporary conditions as well as inherent qualities: "I will be tired after running." "Will you be going to the play tomorrow?" (see below)

The verb "to be" also has some non-copular uses, including:

• As an auxiliary verb:
  • To form the passive voice: "I was told that you wanted to see me"
  • To add continuous aspect to tenses: "It is raining"
• Meaning "to exist": "I want only to be, and that is enough." "There's no sense in making a scientific inquiry about what species the Loch Ness Monster is, without first establishing that the Loch Ness Monster indeed is." "To be or not to be, that is the question."

Note that the auxiliary verb function derives from the copular function; and, depending on one's point of view, one can still interpret the verb as a copula and the following verbal form as being adjectival.

Conjugation

As in most Indo-European languages, the English copula is the most irregular verb, due to constant use. Most English verbs (traditionally known as "weak verbs") have just four separate forms, e.g. "start", "starts", "starting", "started". A large minority of verbs (traditionally known as "strong verbs") have five separate forms, e.g. "begin", "begins", "beginning", "began", "begun". "To be" is a very special case in having eight forms: "be", "am", "is", "are", "being", "was", "were", "been". Traditionally, it had even more, including "art", "wast", "wert", and, occasionally, "best" as a subjunctive. On the history of the paradigm, see: Indo-European copula.

Copulas in other languages

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Languages tend to use copulas in quite different ways.

Chinese

In Chinese languages, both states and qualities are generally expressed with stative verbs with no need for a copula, e.g., "to be tired" (累 lèi), "to be hungry" (饿 è), "to be located at" (在 zài), "to be stupid" (笨 bèn) and so forth. These verbs are usually preceded by an adverb such as 很 hěn ("very") or 不 bù ("not").

Only sentences with a noun as the complement (e.g. "this is my sister") use the verb "to be": 是 shì. This is used frequently: for example, instead of having a verb meaning "to be Chinese", the usual expression is "to be a Chinese person", using 是 shì. Other sentences use adjectives plus the nominaliser 的 de, e.g. 这是红的 zhè shì hóng de "this is red [one".

The history of the Chinese copula 是 is a controversial subject. Before the Han Dynasty, the character served as a demonstrative pronoun meaning "this" (this usage survives in some idioms and proverbs). Some linguists argue that 是 developed into a copula because it often appeared, as a repetitive subject, after the subject of a sentence (in classical Chinese we can say, for example: "George W. Bush, this president of the United States" meaning "George W. Bush is the president of the United States). Other scholars cannot completely accept the explanation, proposing that 是 served as a demonstrative pronoun and a copula at the same time in ancient Chinese. Etymologically, 是 means "straight"; in modern Chinese, 是 means "yes" as an interjection, and "correct", "right" as an adjective, implying a sense of judgement.

N.B. The characters used are simplified ones, and the transcriptions given in italics reflect standard Mandarin pronunciation, using the Pinyin system.

Japanese

Japanese has copulas which would most often be translated as one of the so-called be-verbs of English. The Japanese copula has many forms, including but not limited to da, na, de, and desu. The first and last are used to predicate sentences, while the middle two are used within sentences to modify or connect.

Japanese sentences with copulas most often equate one thing with another, that is, they are of the form "A is B." Examples:

• これはペンです。Kore wa pen desu. "This is a pen" (lit., this TOPIC pen COPULA)
• 僕は学生だ。Boku wa gakusei da "I am a student" (lit., I-MASCULINE TOPIC student COPULA)

The following examples show the use of the copula as a modifier or connector.

• 医者のおじ。 Isha no oji. "Uncle who is a physician." (lit., physician COPULA uncle)
• 好きでたまらない。 Suki de tamaranai. "I love it so much I'm gonna burst!" (lit., like COPULA not-be-able-to-bear)

The difference between da and desu is simple: desu is more formal and polite than da. Thus, the two sentences below are identical in meaning and differ only in their politeness.

• あれはホテルだ。Are wa hoteru da. "That is a hotel." (lit., that TOPIC hotel COPULA)
• あれはホテルです。Are wa hoteru desu. "That is a hotel." (lit., that TOPIC hotel COPULA)

Japanese sentences may be predicated with copulas or with verbs. However, desu may not always be a predicate. In some cases, its only function is to make a sentence predicated with a stative verb more polite. In a sense, there are two words desu in Japanese: one is a polite copula that predicates sentences, and the other is a politeness marker added to stative verbs. However, da always functions as a predicate, so it cannot be combined with a stative verb, because sentences need only one predicate. See the examples below.

• このビールはうまい。Kono biiru wa umai. "This beer is good." (lit., this beer TOPIC be-tasty)
• このビールはうまいです。Kono biiru wa umai desu. "This beer is good." (lit., this beer TOPIC be-tasty POLITE)

but

• このビールはうまいだ。Kono biiru wa umai da is an unacceptable usage of da, because da may only serve as a predicate.

Japanese also has two verbs corresponding to English "to be": aru and iru. Neither of them is a copula. Aru is used for inanimate objects, including plants, while iru is used for people and animals, though there are exceptions to this generalization. Different usages of the copula, stative verbs, and the two verbs of being are shown below.

• 本はテーブルにある。Hon wa teeburu ni aru. "The book is on the table."
• キムさんはここにいる。Kimu-san wa koko ni iru. "Kim is here."
• 私はアメリカ人だ。Watashi wa amerikajin da. "I am an American."
• 純子さんは変だ。Junko-san wa hen da. "Junko is strange."
• これは楽しい。Kore wa tanoshii. "This is fun."

"Desu" is actually the shortened form of the verb of ではあります（dewa arimasu), to make a sentence polite this could be used. As could be ございます　(gozaimasu) used in a really proper form of desu.

Indo-European languages

In Indo-European languages, the words meaning "to be" (originating in stem *es) often sound similar to each other. Due to the high frequency of their use, their inflection retains a considerable degree of similarity in some cases. Thus, for example, the English form is is an apparent cognate of German ist, Latin est and Russian jest', in spite the fact that the Germanic, Romance, and Slavic language groups split at least three thousand years ago.

A feature of most Romance languages is the coexistence of two different verbs meaning "to be", the main one from the Latin sum, and a secondary one from sto (see Romance copula). The difference is that the former usually refers to essential characteristics, whilst the latter refers to states and situations, e. g. "Bob is old" versus "Bob is well". (Note that the English words just used, "essential" and "state", are also cognate with the Latin roots esse and stare.)

• Italian Bob è vecchio — Bob is old
• Italian Bob sta bene — Bob is well

• Spanish Bob es viejo — Bob is old
• Spanish Bob está bien — Bob is well

• Portuguese Bob é velho — Bob is old
• Portuguese Bob está bem — Bob is well

In some cases, the verb itself changes the meaning of the adjective/sentence. For example, in Portuguese: "Bob está velho" (Bob has grown old); "Bob é velho" (Bob is old). "Bob está bom" (Bob is well. Depending on the context, it can mean that Bob was not well, bus now he is); "Bob é bom" (Bob is kind). "Bob está parvo" (Bob is acting silly); "Bob é parvo" (Bob is silly).

In Spanish, for example, the quite high degree of verbal inflection, plus the existence of two copulae (ser and estar), means that there are 105 separate forms to express the eight of English, and one of Chinese.

In certain languages there are not only two copulae but the syntax is also changed when one is distinguishing between states or situation and essential characteristics. For example, in Irish, describing the subject's state or situation typically uses the normal VSO ordering with the verb bí. The copula is, which is used to state essential characteristics or equivalences, requires a change in word order so that the subject does not immediately follow the copula (see Irish syntax).

Russian and Hungarian

In languages such as Russian or Hungarian, the copula in present tense is implied rather than spoken (Russian: я — человек, ya — chelovek "I (am) a human"; Hungarian: ő ember, "he (is) a human"). This usage (also common in Semitic languages), is known generically as the zero copula. Note that in other tenses (sometimes in other persons besides singular third) the copula usually reappears.

In Hungarian, zero copula is restricted to present tense in 3rd person singular and plural (see examples above): "Ő ember/Ők emberek — "s/he is a human"/"they are humans"; but: "(én) ember vagyok" — "I am a human", "(te) ember vagy" — "you are a human", "(mi) emberek vagyunk" — "we are humans", "(ti) emberek vagytok" — "you (all) are humans". It also reappears for stating locations: "az emberek a házban vannak" — "the people are in the house".

To recycle the above examples ("Bob is old" versus "Bob is here"), Hungarian only uses a copula in the latter case (and this not only with regard to third person singular/plural) (Itt van Róbert), but not in the first example (Róbert öreg). This is to relate a subject to a more temporary condition/state taking place in space (very often in the sense of Lojban zvati — "la rabyrt. zvati ne'i le zdani" (Robert is in the house)).

In Russian, the verb "быть" (byt’) is the infinitive of "to be". The third person singular, "есть" (yest’) means "is" (and, interestingly enough, it is a homonym of the infinitive "to eat"). As a copula, it can be inflected into the past ("был", byl), future ("будет", budet), and subjunctive ("был" or "бы", byl or by) forms. A present tense ("есть", yest’) exists; however, it is almost never used as a copula, but rather omitted altogether or replaced by the verb "являться" (yavlyat'sa) (to be in essence). Thus one can say:

• Она была красивой (Ona byla krasivoy) — "she was beautiful" (adjective in instrumental case).
• Она красивая (Ona krasivaya) — "she is beautiful" (adjective in the nominative case).
• Она является красивой (Ona yavlyayetsya krasivoy) — "she is beautiful" (adjective also in instrumental).

But not (except for archaic effect):

• Она есть красивая (Ona yest’ krasivaya) — "she is beautiful".

The third person plural "суть" (sut’) ("are") is still used in some standard phrases (but since it is a homonym of the noun "essence", most native speakers do not notice it to be a verb):

• Они суть одно и то же (Oni sut’ odno i to zhe) — "they are one and the same".

Turkish

(See also the separate article on the Turkish copula.)

Unlike Indo-European languages, being an extremely regular agglutinative language, Turkish forms its "being" not as a regular verb, rather as an auxiliary verb denoted as "i-mek" which shows its existence only through suffixes to predicates which can be nouns, adjectives or arguably conjugated verb stems.

In the third person singular, just like in Hungarian or Russian zero copula is the case.

For example:

• Deniz mavi. = "^* sea is blue" (the auxiliary verb "i-mek" is implied only)
• Ben maviyim = "I am blue" (the auxiliary verb "i-mek" appears in "(y)im".)

Georgian

Just like in English, the verb "to be" (qopna) is irregular in Georgian; different verb roots are employed in different tenses. The roots -ar-, -kn-, -qav-, and -qop- (past participle) are used in the present tense, future tense, past tense and the perfective tenses respectively. Examples:

Masc'avlebeli var ("I am a teacher")

Masc'avlebeli viknebi ("I will be a teacher")

Masc'avlebeli viqavi ("I was a teacher")

Masc'avlebeli vqopilvar ("I have been a teacher")

Masc'avlebeli vqopiliqavi ("I had been a teacher")

Note that in the last two examples (perfective and pluperfective) two roots are used in one verb compound. In the perfective tense, the root qop (which is the expected root for the perfective tense) is followed by the root ar, which is the root for the present tense. In the pluperfective tense, again, the root qop is followed by the past tense root qav. This formation is very similar to German. In German, the perfective and the pluperfective are expressed in this way:

Ich bin ein Lehrer gewesen ("I have been a teacher")

Ich war ein Lehrer gewesen ("I had been a teacher")

Here, gewesen is the past participle of sein ("to be") in German. In both examples, just like in Georgian, this participle is used together with the present and the past forms of the verb in order to conjugate for the perfect and the pluperfect tenses.

Nahuatl

Nahuatl, as well as some other Amerindian languages, has no copula. Instead of using a copula, it is possible to conjugate nouns or adjectives like verbs.

Siouan languages

In Siouan languages like Lakota, this is similar as in principle almost all words - according to their structure - are verbs. So, not very unlike in Lojban (see below), not only (transitive, intransitive and so-called 'stative') verbs but even nouns often behave like verbs - and do not need to have copulas. E.g. _wicasa_ - man/adult male, to-be-a-man -> wimacasa/winicasa/he wicasa (I am/you are/he is a man). Yet, there also is a verb (copula) _heca_ [he'cha (to be a such) that in most cases is used: "wicasa hemaca/henica/heca" (I am/you are/he is a man). So, in order to express that I am a doctor of profession, I have to say: "pezuta wicasa hemaca" wicha's^a hema'cha. But in order to express that I'm THE doctor (say, that had been phoned to help), I'd have to use another copula _(i)ye_ (to be the one): "pezuta wicasa (kin) miye lo" (medicine-man DEF ART I-am-the-one MALE ASSERT).

In order to refer to space (e.g. Robert is in the house), various verbs are used as copula, e.g. _yankA_ (lit.: to sit) for humans, _han/he_ [haN'/he' (to stand upright) for inanimates of a certain shape. So, "Robert is in the house" could be translated as "Robert timahel yanke (yelo)", whereas "there's one restaurant next to the gas station" translates as "owotetipi wigli-oinazin kin hel isakib wanzi he".

• Essay on Lakota syntax

Artificial languages

The artificial language Lojban has copula, but they are rarely used, and are sometimes viewed with distaste in the Lojban community, because all words that express a predicate can be used as verbs. The three sentences above would all have the same form in Lojban: la bob. bajra, la bob. tolcitno, and la bob. fagdirpre. There are several different copula: me turns whatever follows the word me into a verb that means to be what it follows. For example, me la bob. means to be Bob. Another copula is du, which is a verb that means all its arguments are the same thing (equal) ^*.

The E-Prime language, based on English, simply avoids the issue by not having a generic copula. It requires instead a specific form such as "remains", "becomes", "lies", or "equals".

Esperanto uses the copula much as in English. The infinitive is esti, and the whole conjugation is regular (as with all Esperanto verbs). Additionally, adjectival roots can be turned into stative verbs: La ĉielo bluas. "The sky is blue."

In Toki Pona, if the subject is mi (I) or sina (you, sg.) there is no copula needed; otherwise, li is used just before the verb. For example: "sina pona" (you're good), "meli li pona" ((the) woman is good).

Existential usage

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The existential usage of "to be" is distinct from and yet, in some languages, intimately related to its copulative usage. In language as opposed to formal logic, existence is a predicate rather than a quantifier, and the passage from copulative to existential usage can be subtle.

For example:

• Japanese: 吾輩は猫である。名前はまだない。 Wagahai wa neko de aru. Namae wa mada nai – I am a cat. As yet, I have no name. — Soseki Natsume
• English: To be or not to be, that is the question. — William Shakespeare
• English: climb Mount Everest? Because it is there. — George Mallory
• Russian: Страна, которую ищут дети, есть kotoruju ishchut djeti, jest' – That land we yearn for in our childhood is there. — Prishvin
• French: Je pense, donc je suis. – I think, therefore I am. — Descartes
• Latin: Cogito ergo sum. — I think, therefore I am. — Descartes
• Turkish: Düşünüyorum, öyleyse varım. – I think, therefore I am. — Descartes

Other languages prefer to keep the existential usage entirely separate from the copula. Swedish, for example, reserves vara for the copula, keeping bli (to become) and finnas (to be found) for becoming and existing, respectively.

• Swedish: Vem vill bli miljonär? — Who wants to be a millionaire?. — Bengt Magnusson
• Swedish: Varför bestiga Mt. Everest? Därfor att det finns där. — Why climb Mt. Everest? Because it is there. — George Mallory

In ontology, philosophical discussions of the word "be" and its conjugations takes place over the meaning of the word is, the third person singular form of 'be', and whether the other senses can be reduced to one sense. For example, it is sometimes suggested that the "is" of existence is reducible to the "is" of property attribution or class membership; to be, Aristotle held, is to be something. Of course, the gerund form of "be", being, is its own (vexed) topic: see being and existence.

Copula as subset relator

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From one perspective, the copula always relates two things as subsets. Take the following examples:

1. John is a doctor.
2. John and Mary are doctors.
3. Doctors are educated.
4. Mary is running.
5. Running is fun.

Example 1 includes John in the set of all doctors. Example 2 includes John and Mary both in the set of all doctors. Example 3 includes the set of doctors in the set of those who are educated.

Example 4 is different. Example 4 includes Mary's state at the time of utterance in the set of states consistent with running. Example 5 then includes the set of states consistent with running in the set of states consistent with fun.

Parts of speech | Verb types

Kopula | Koopula | Copail | Pomoćni glagoli | Kopula | コピュラ | Kopula