# Indo-European copula

A feature common to all Indo-European languages is the presence of a verb corresponding to the English verb to be.

## General features

This verb has two basic meanings:
* In a less marked context it is a simple copula (I’m tired; That’s a shame!), a function which in non-Indo-European languages can be expressed quite differently.
* In a more heavily marked context it expresses existence (I think therefore I am); the dividing line between these is not always easy to draw.
Some languages have shared these functions between several verbs: Irish, Spanish and Persian all have multiple equivalents of to be, making a variety of distinctions.
Many Indo-European languages also use the verb "to be" as an auxiliary for the formation of compound (periphrastic) tenses (I’m working; I was bitten). Other functions vary from language to language. For example, although in its basic meanings, to be is a stative verb, English puts it to work as a dynamic verb in fixed collocations (You are being very annoying).
The copula is the most irregular verb in many Indo-European languages. This is partly because it is more frequently used than any other, and partly because Proto-Indo-European offered more than one verb suitable for use in these functions, with the result that the daughter languages, in different ways, have tended to form suppletive verb paradigms.
This article describes the way in which the irregular forms have developed from a series of roots.

## The Proto-Indo-European [PIE] roots
### *h$_1$es-

The root *h$_1$es- was certainly already a copula in Proto-Indo-European.
The e-grade *h$_1$es- (see Indo-European ablaut) is found in such forms as English is, Irish is, German ist, Latin est, Sanskrit asti, Persian ast, Old Church Slavonic jestĭ.
The zero grade *h$_1$s- produces forms beginning with /s/, like German sind, Latin sumus, Vedic Sanskrit smas, etc.
In PIE, *h$_1$es- was an athematic verb in -mi; that is, the first person singular was *h$_1$esmi; this inflection survives in English am, Pashto yem, Persian am, Sanskrit asmi, Bengali first-person verb ending -ām, Old Church Slavonic esmĭ, etc.
This verb is generally reconstructed for Proto-Indo-European thus:
| Person | Present indicative | Imperfect indicative | Subjunctive | Optative | Imperative |
| 1st singular | *h$_1$és-mi | *h$_1$és-m̥ | *h$_1$és-oh$_2$ | *h$_1$s-iéh$_1$-m | — |
| 2nd singular | *h$_1$és-i | *h$_1$és | *h$_1$és-esi | *h$_1$s-iéh$_1$-s | *h$_1$és, *h$_1$s-dʰí |
| 3rd singular | *h$_1$és-ti | *h$_1$és-t | *h$_1$és-eti | *h$_1$s-iéh$_1$-t | *h$_1$és-tu |
| 1st dual | *h$_1$s-uós | *h$_1$s-ué | *h$_1$és-owos | *h$_1$s-ih$_1$-wé | — |
| 2nd dual | *h$_1$s-tés | *h$_1$s-tóm | *h$_1$és-etes | *h$_1$s-ih$_1$-tóm | *h$_1$s-tóm |
| 3rd dual | *h$_1$s-tés | *h$_1$s-tā́m | *h$_1$és-etes | *h$_1$s-ih$_1$-tā́m | *h$_1$s-tā́m |
| 1st plural | *h$_1$s-m̥ós | *h$_1$s-m̥é | *h$_1$és-omos | *h$_1$s-ih$_1$-mé | — |
| 2nd plural | *h$_1$s-té | *h$_1$s-té | *h$_1$és-ete | *h$_1$s-ih$_1$-té | *h$_1$s-té |
| 3rd plural | *h$_1$s-énti | *h$_1$s-énd | *h$_1$és-onti | *h$_1$s-ih$_1$-énd | *h$_1$s-éntu |

### *bʰuH-

The root *bʰuH- or *bʰuh₂- (which did not have ablaut variations in the protolanguage) probably meant 'to grow', but also 'to become'.
This is the source of the English infinitive be and participle been. Also, for example, the Scottish Gaelic "future" tense bithidh; the Irish imperative bí, past bhí and future beidh; the Welsh bod (along with the other b- initial forms); Persian imperative bov, past bud and future bâš; and the Slavic infinitive and past, etc. for example Russian быть (byt’), был (byl).
PIE *bʰ became Latin /f/, hence the Latin future participle futūrus and perfect fuī; Latin fīō 'I become' is also from this root, as is the Greek verb φύω (phúō), from which physics and physical are derived.
*bʰuH- was a preterito-present verb, i.e. Imperfect endings for Present, and can be reconstructed as follows:
| Person | Indicative | Subjunctive | Optative | Imperative |
| 1st singular | *bʰúH-m | *bʰúH-oh$_2$ | *bʰuH-yéh$_1$-m | — |
| 2nd singular | *bʰúH-s | *bʰúH-esi | *bʰuH-yéh$_1$-s | *bʰúH, *bʰuH-dʰí |
| 3rd singular | *bʰúH-t | *bʰúH-eti | *bʰuH-yéh$_1$-t | *bʰúH-tu |
| 1st dual | *bʰuH-wé | *bʰúH-owos | *bʰuH-ih$_1$-wé | — |
| 2nd dual | *bʰuH-tóm | *bʰúH-etes | *bʰuH-ih$_1$-tóm | *bʰuH-tóm |
| 3rd dual | *bʰuH-tā́m | *bʰúH-etes | *bʰuH-ih$_1$-tā́m | *bʰuH-tā́m |
| 1st plural | *bʰuH-mé | *bʰúH-omos | *bʰuH-ih$_1$-mé | — |
| 2nd plural | *bʰuH-té | *bʰúH-ete | *bʰuH-ih$_1$-té | *bʰuH-té |
| 3rd plural | *bʰuH-énd | *bʰúH-onti | *bʰuH-ih$_1$-énd | *bʰuH-éntu |

### *h$_2$wes-

The root *h$_2$wes- may originally have meant "to live", and has been productive in all Germanic languages. The e-grade is present in the German participle gewesen, the o-grade (*wos-) survives in English and Old High German was, while the lengthened e-grade (*wēs-) gives us English were. (The Germanic forms with /r/ instead of /s/ result from grammatischer Wechsel.) See Germanic strong verb: Class 5.

### *h$_1$er-

This has been claimed as the origin of the Old Norse and later Scandinavian languages' present stem: Old Norse em, ert, er, erum, eruð, eru; the second person forms of which were borrowed into English as art and are. It has also been seen as the origin of the Latin imperfect (eram, eras, erat) and future tenses (ero, eris, erit).
However, other authorities link these forms with *h$_1$es- and assume grammatischer Wechsel (/s/→/r/), although this is not normally found in the present stem. Donald Ringe argues that the copula was sometimes unaccented in Pre-Proto-Germanic, which would have then triggered the voicing under Verner's law. He explains the Germanic first person singular form *immi as such, deriving it from earlier *ezmi, since -zm-, but not -sm-, was assimilated to -mm- in Germanic (for which other evidence exists as well). Furthermore, the third person plural form *sindi (from PIE *h₁sénti) shows that this word, too, was unaccented. If the accent had been preserved, it would have become *sinþi, but that form is not found in any Germanic language. In this view, it is likely that stressed and unstressed varieties of the copula (with corresponding voiceless and voiced fricatives) existed side by side in Germanic, and the involvement of a separate root *h₁er- is unnecessary.
The Latin forms could be explained by rhotacism.

### *steh$_2$-

The root *(s)teh$_2$- meant "to stand". From this root comes the present stem of the so-called "substantive verb" in Irish and Scottish Gaelic, tá and tha respectively, as well as taw in Welsh. On the absence of the initial s- in Celtic, see Indo-European s-mobile.
In Latin, stō, stare retained the meaning "to stand", until local forms of Vulgar Latin began to use it as a copula in certain circumstances. Today, this survives in that several Romance languages (Galician-Portuguese, Spanish, Catalan) use it as one of their two copulae, and there is also a Romance tendency for a past participle derived from *steh$_2$- to replace the original one of the copula (this occurs in French, Italian and the main dialects of Catalan). See also Romance copula.
Although in Dutch this verb retains its primary meaning of "stand", it is used in an auxiliary-like function that only has a secondary meaning of "standing", for example: ik sta te koken ("I am cooking", literally "I stand to cook"). While it is not a full copula (it can normally only be used as an auxiliary with another verb), it does have shades of meaning that resemble that of the Italian sto cucinando ("I am cooking"). The intransitive verbs zitten ("to sit"), liggen ("to lie") and lopen ("to walk/run") are used in similar ways.
In Swedish, which usually lacks gerund forms, the corresponding stå is often used similarly, along with sitta ("to sit"), ligga ("to lie") and gå ("to walk").
In Hindustani the past tense of the copula honā "to be" which are «tʰā», «tʰe», «tʰī» and «tʰī̃» are derived from Sanskrit «stʰā». Gujarati has a cognate verb «tʰavũ» "to happen"; cf. Bengali aorist «tʰā-» (to stay) as well.

## The resulting paradigms
### Indo-Iranian languages
#### Indic languages
##### Sanskrit

The Vedic Sanskrit root as (to be) is derived from the Indo-European root *h$_1$es-.
| Mood/Tense | Mood/Tense | Indicative | Indicative | Indicative | Indicative | Indicative | Optative | Imperative |
| Mood/Tense | Mood/Tense | Present | Present | Perfect | Imperfect | Periphrasatic Future | Optative | Imperative |
| Voice | Voice | Active | Passive | Perfect | Imperfect | Periphrasatic Future | Optative | Imperative |
| singular | 1st | asmi | he | āsa | āsam | asitāsmi | syām | asāni |
| singular | 2nd | asi | se | āsitha | āsīḥ | asitāsi | syāḥ | edhi |
| singular | 3rd | asti | ste | āsa | āsīt | asitā | syāt | astu |
| dual | 1st | svaḥ | svahe | āsiva | āsva | asitāsvaḥ | syāva | asāva |
| dual | 2nd | sthaḥ | sāthe | āsathuḥ | āstam | asitāsthaḥ | syātam | stam |
| dual | 3rd | staḥ | sāte | āsatuḥ | āstām | asitārau | syātām | stām |
| plural | 1st | smaḥ | smahe | āsima | āsma | asitāsmaḥ | syāma | asāma |
| plural | 2nd | stha | dhve | āsa | āsta | asitāstha | syāta | sta |
| plural | 3rd | santi | sate | āsuḥ | āsan | asitāraḥ | syuḥ | santu |
bhū (to be) is derived from Indo-European *bʰuH-.
| Mood/Tense | Mood/Tense | Indicative | Indicative | Indicative | Indicative | Indicative | Indicative | Indicative | Conditional | Optative | Optative | Aorist | Aorist | Injunctive | Injunctive | Benedictive | Imperative | Imperative |
| Mood/Tense | Mood/Tense | Present | Present | Perfect | Imperfect | Imperfect | Future | Periphrasatic Future | Conditional | Optative | Optative | Aorist | Aorist | Injunctive | Injunctive | Benedictive | Imperative | Imperative |
| Voice | Voice | Active | Passive | Perfect | Active | Passive | Future | Periphrasatic Future | Conditional | Active | Passive | Active | Passive | Active | Passive | Benedictive | Active | Passive |
| singular | 1st | bhavāmi | bhūye | babhūva | abhavam | abhūye | bhaviṣyāmi | bhavitāsmi | abhaviṣyam | bhaveyam | bhūyeya | abhūvam | | bhūvam | | bhūyāsam | bhavāni | bhūyai |
| singular | 2nd | bhavasi | bhūyase | babhūvitha | abhavaḥ | abhūyathāḥ | bhaviṣyasi | bhavitāsi | abhaviṣyaḥ | bhaveḥ | bhūyethāḥ | abhūḥ | | bhūḥ | | bhūyāḥ | bhava | bhūyasva |
| singular | 3rd | bhavati | bhūyate | babhūva | abhavat | abhūyata | bhaviṣyati | bhavitā | abhaviṣyat | bhavet | bhūyeta | abhūt | abhāvi | bhūt | bhāvi | bhūyāt | bhavatu | bhūyatām |
| dual | 1st | bhavāvaḥ | bhūyāvahe | babhūviva | abhavāva | abhūyāvahi | bhaviṣyāvaḥ | bhavitāsvaḥ | abhaviṣyāva | bhaveva | bhūyevahi | abhūva | | bhūva | | bhūyāsva | bhavāva | bhūyāvahai |
| dual | 2nd | bhavathaḥ | bhūyethe | babhūvathuḥ | abhavatam | abhūyethām | bhaviṣyathaḥ | bhavitāsthaḥ | abhaviṣyatam | bhavetam | bhūyeyāthām | abhūtam | | bhūtam | | bhūyāstam | bhavatam | bhūyethām |
| dual | 3rd | bhavataḥ | bhūyete | babhūvatuḥ | abhavatām | abhūyetām | bhaviṣyataḥ | bhavitārau | abhaviṣyatām | bhavetām | bhūyeyātām | abhūtām | | bhūtām | | bhūyāstām | bhavatām | bhūyetām |
| plural | 1st | bhavāmaḥ | bhūyāmahe | babhūvima | abhavāma | abhūyāmahi | bhaviṣyāmaḥ | bhavitāsmaḥ | abhaviṣyāma | bhavema | bhūyemahi | abhūma | | bhūma | | bhūyāsma | bhavāma | bhūyāmahai |
| plural | 2nd | bhavatha | bhūyadhve | babhūva | abhavata | abhūyadhvam | bhaviṣyatha | bhavitāstha | abhaviṣyata | bhaveta | bhūyedhvam | abhūta | | bhūta | | bhūyāsta | bhavata | bhūyadhvam |
| plural | 3rd | bhavanti | bhūyante | babhūvuḥ | abhavan | abhūyanta | bhaviṣyanti | bhavitāraḥ | abhaviṣyan | bhaveyuḥ | bhūyeran | abhūvan | | bhūvan | | bhūyāsuḥ | bhavantu | bhūyantām |

##### Hindi-Urdu

In modern Hindi-Urdu (Hindustani), the Sanskrit verb अस् (as) (to be) which is derived from the Indo-European root *h$_1$es- has developed into the present indicative forms of the verb होना ہونا (honā) (to be). The infinitive होना ہونا (honā) itself is derived from the Sanskrit verb root भू (bʱū) which is derived from Indo-European root *b$^h$uH-. The indicative imperfect forms of होना ہونا (honā) comes from Sanskrit स्थित (stʰita) "standing, situated" which are derived from the PIE root *steh₂- (“to stand”). होना ہونا (honā) is the only verb in Hindi-Urdu to have the present indicative, imperfect indicative, presumptive mood and the present subjunctive conjugations, and all the other verbs in Hindi-Urdu lack them.
The verb होना / ہونا (honā) can be translated as "to be", "to exist", "to happen" or "to have" depending on the context, and when used in the third person it could also be translated as "there is/are". Many verbs conjugations in Hindi-Urdu are derived from participles and hence are gendered and numbered, and they agree with either the object or the subject of the sentence depending on the grammatical case of the subject of the sentence. When the subject is in the ergative or the dative case (seeː dative construction & quirky subject) the verb agrees in gender and number with the object of the sentence and with the subject when the subject is in the nominative case.
PERSONAL FORMS of "honā (to be)" :
| mood | tense | first person | first person | second person | second person | second person | second person | second person | second person |
| mood | tense | singular | singular | familiar$^{1,2}$ | familiar$^{1,2}$ | intimate | intimate | formal$^{1,2,3}$ | formal$^{1,2,3}$ |
| mood | tense | ♂ | ♀ | ♂ | ♀ | ♂ | ♀ | ♂ | ♀ |
| indicative | present | hū̃ | hū̃ | ho | ho | hai | hai | ha͠i | ha͠i |
| indicative | perfect | huā | huī | hue | huī | huā | huī | hue | huī̃ |
| indicative | imperfect | thā | thī | the | thī | thā | thī | the | thī̃ |
| indicative | future | hoū̃gā | hoū̃gī | hooge | hoogī | hoegā | hoegī | hoẽge | hoẽgī |
| presumptive | all | hū̃gā | hū̃gī | hoge | hogī | hogā | hogī | hõge | hõgī |
| subjunctive | present | hū̃ | hū̃ | ho | ho | ho | ho | hõ | hõ |
| subjunctive | future | hoū̃ | hoū̃ | hoo | hoo | hoe | hoe | hoẽ | hoẽ |
| subjunctive | future$^5$ | huā | huī | hue | huī | huā | huī | hue | huī̃ |
| contrafactual | past | hotā | hotī | hote | hotī | hotā | hotī | hote | hotī̃ |
| imperative | present | — | — | hoo | hoo | ho | ho | hoiye | hoiye |
| imperative | future | — | — | honā | honā | hoiyo | hoiyo | hoiyegā | hoiyegā |
IMPERSONAL FORMS of "honā (to be)" :
| Stem | ho | ho | ho | ho |
| Infinitive | honā | honā | honā | honā |
| Oblique Infinitive | hone | hone | hone | hone |
| Conjunctive | hokar, hoke | hokar, hoke | hokar, hoke | hokar, hoke |
| Progressive | hote-hote | hote-hote | hote-hote | hote-hote |
| PARTICIPLES | ♂ | ♂ | ♀ | ♀ |
| PARTICIPLES | singular | plural | singular | plural |
| Infinitive | honā | hone | honī | honī̃ |
| Prospective | honevālā | honevāle | honevālī | honevālī̃ |
| Agentive | honevālā | honevāle | honevālī | honevālī̃ |
| Habitual Aspect | hotā | hote | hotī | hotī̃ |
| Perfective Aspect | huā | hue | huī | huī̃ |
| Perfective Adjectival$^4$ | huā-huā | hue-hue | huī-huī | huī-huī̃ |
| Imperfective Adjectival$^4$ | hotā-huā | hote-hue | hotī-huī | hotī-huī̃ |
$^1$ the second person familiar and formal conjugations are grammatically plural and can be used in both singular and plural sense, akin to the English pronoun you. :
$^2$ the third person singular and plural conjugations are respectively the same as the second person intimate and formal conjugations. :
$^3$ the first person plural pronoun conjugations are the same as the second person formal conjugations. :
$^4$ the second (adjoined) part of the adjectival participles -huā, -hue, -huī & -huī̃ are respectively shortened to -wā, -we, -wī & -wī̃ in speech. :
$^5$ the future perfective subjunctive has the same form as the indicative perfect. It is only used with if-clauses and relative clauses. :

##### Bengali

Bengali is considered a zero copula language, however there are notable exceptions. In the simple present tense there is no verb connecting the subject to the predicative (the "zero verb" copula) but when the predicate expresses ideas of existence, location, or possession, for such cases the verb আছ- (ach) can be roughly translated as "to exist" or "to be present".
* In the past tense, the incomplete verb আছ- (ach) is always used as the copula, regardless of the nature of the predicative.
* For the future tense and non-finite structures, the copula is supplied by the verb হওয়া (howa), with the exceptions being the possessive and locative predicatives for which the verb থাকা (thaka, "to remain") is utilized.
* Bengali does not have a verb for possession (i.e. "to have", "to own"). Instead, possession in Bengali is expressed by the verb আছ- (āch) (for present and past tenses) and the verb থাকা (thaka) (for future tense) inflected with the possessed object and a genitive case for the possessor.
Bengali verbs are highly inflected and are regular with only few exceptions. They consist of a stem and an ending; they are traditionally listed in Bengali dictionaries in their "verbal noun" form, which is usually formed by adding -a to the stem: for instance, করা (kôra, to do) is formed from the stem কর (kôr). The stem can end in either a vowel or a consonant.

##### Nepali

The copula verb of Nepali has two sets of conjugations. The हो (ho) set is used in sentences that equate two things, like त्यो किताब हो (tyo kitāb ho, “That is a book.”) The छ (cha) set is used in sentences that describe something, or locate where something is, like त्यो ठूलो छ (tyo ṭhūlo cha, “That is big.”). Singular present tense forms of the copulas in Nepali are shown in the table below:
| Pronoun | Pronoun | Pronoun | हो (ho, “define/identify”) | हो (ho, “define/identify”) | छ (cha, “describe/qualify”) | छ (cha, “describe/qualify”) |
| Pronoun | Pronoun | Pronoun | Positive | Negative | Positive | Negative |
| 1st | 1st | म (ma) | हुँ (hũ) | होइन (hoina) | छुँ (chũ) | छैन (chaina) |
| 2nd | Familiar | तिमी (timī) | हौ (hau) | होइनौ (hoinau) | छौ (chau) | छैनौ (chainau) |
| 2nd | Formal | तपाईं (tapāīṃ) | हुनुहुन्छ (hunuhuncha) | हुनुहुन्न (hunuhunna) | हुनुहुन्छ (hunuhuncha) | हुनुहुन्न (hunuhunna) |
| 3rd | Familiar | यो (yo) / त्यो (tyo) | हो (ho) | होइन (hoina) | छ (cha) | छैन (chaina) |
| 3rd | Formal | वहाँ (vahā̃) | हुनुहुन्छ (hunuhuncha) | हुनुहुन्न (hunuhunna) | हुनुहुन्छ (hunuhuncha) | हुनुहुन्न (hunuhunna) |

#### Iranic languages
##### Persian

With regard to the function of the verb ‘to be’ as a copula, the most conspicuous feature of Modern Persian language is the evolution of an existential be, hast (exists), out of ast (is). In fact, when studying the forms and functions of ‘to be’, one might find certain characteristics specific to Persian that are worth pondering upon— i.e. even without considering the diachronic evolution of Modern Persian language and its relation to Ancient Iranian languages (such as Old Persian and Avestan) whose usage of the verb ‘to be’ seems more close to Sanskrit. Paradoxically, despite the fact that Persian is apparently the only Indo-European language that has created an existential be out of the copula, it has simultaneously made an extreme use of the latter to produce a general paradigm for conjugating all Persian verbs.
Historically speaking, like most of Indo-European languages that make use of suppletive roots to denote ‘to be’, Persian integrates Proto-Indo-European (PIE) verbs *h$_1$es- (to be) and *b$^h$uH (to grow> to become> to be). Hence, while Persian infinitive būdan (to be) < PIE *b$^h$uH forms the past stem of the verb (e.g. Persian būd- ‘was’) or acts as an auxiliary verb in formation of pluperfect of other verbs, its present tense is solely based on the derivatives of PIE *h$_1$es-. It is, in fact, from the declension of PIE *h$_1$es- (to be) that six present stems have been created and assigned to the 1st, 2nd, and 3rd person singular and plural to act as the present-tense conjugation of Persian būdan (to be), as shown in the following table.
| | Persian | English | Persian | English |
| 1st Person | -am | (I) am | -īm | (we) are |
| 2nd Person | -ī | (thou) art | -īd | (you) are |
| 3rd Person | ast (a) | (he/she/it) is | -and | (they) are |
As an example, in the following sentences, the present forms of the verb 'to be' are used as copulas or predicates:
| Persian | English |
| man doxtar-e to am. | I am thy daughter. |
| īn barādar-e man ast (a or e). | This is my brother. |
| to pedar-e man ī. | Thou art my father. |
Furthermore, as endings added to the stem of the verbs, these declensional forms have been grammaticalized to shape a general paradigm for the grammatical conjugation of all other verbs; these endings were once auxiliary verbs which evolved into an enclitic. This generalized conjugational paradigm is also applied to the past tense of the verb būdan (shown in the table below). However, what is linguistically notable, is the emergence of an existential be out of the copula, viz hast (exists) out of ast (is). The evolution of this exceptional form, might go back to ancient Iranian languages, where ast could have two variants (cf. Avestan which has both as- and has- <PIE *h$_1$es- ‘be’). In the next phase, what we may call a pseudo-verb appeared, vis. the verb hastan (to exist) has been analogically evolved from hast (exists) and has been conjugated like any other Persian verb (e.g. hast-am = literally: *‘(I) am existence’→ ‘I exist’).
The simple past conjugation of the verb būdan (to be) is in fact formed by a double-copula, in the sense that both the stem and the ending are copulas: the past stem of the verb būd- is derived from PIE *b$^h$uH-, while the endings are from the suppletive form of PIE *h$_1$es- (to be) with the exception of 3rd person singular which has zero ending for the all Persian verbs in the past tense.
| Singular | English | Enclitic copula | Plural | English | Enclitic copula |
| būdam | I was | ام -am | būdīm | we were | ايم -īm |
| būdī | thou wast | اى -ī | būdīd | you were | اید -īd |
| būd (būda) | he/she/it was | Ø (a) | būdand | they were | اند -and |
The present perfect conjugation of the verb būdan (to be) is a double copula paradigm as it is produced by addition of all enclitic copulas to the past participle of the verb: būde (been).
| Singular | English | Enclitic copula | Plural | English | Enclitic copula |
| būdeam | I have been | -am | būdeīm | we have been | -īm |
| būdeī | thou hast been | -ī | būdeīd | you have been | -īd |
| būde ast (būde a) | he/she/it has been | ast (a) | būdeand | they have been | -and |
The pseudo-verb hastan (to exist) has only simple present tense; in addition, it is truly and purely existencial only in the case of third person singular (hast). The fact is that the verb has been the product of this very case, as an "existential is", hast (he/she/it exists). For other persons the conjugation has to use enclitic copulas. These copulas are, in turn, derived from the declension of PIE *h$_1$es- (to be); as if the predicative "to be" has been an auxiliary verb turned into enclitic, to provide six endings for 1st/2nd/3rd person (singular & plural). However, as it is said, the 3rd person singular has no ending in the case of hastan. That is to say that the existential hast (exists), which is like the alter-ego of the copula ast (is), takes no ending, while the present stem of all other verbs take an archaic ending -ad in their 3rd person singular.
| Singular | English | Enclitic copula | Plural | English | Enclitic copula |
| hastam | I exist | -am | hastīm | we exist | -īm |
| hastī | thou existest | -ī | hastīd | you exist | -īd |
| hast | he/she/it exists | {ad} > Ø (a) | hastand | they exist | -and |

### Hellenic languages
#### Greek

The Ancient Greek verb eimi (I am) is derived from the Indo-European root *h$_1$es-.
| | | Homeric Greek | Classical Attic | Modern Greek |
| Present indicative | 1st sg. 2nd sg. 3rd sg. 1st pl. 2nd pl. 3rd pl. | εἰμί (eimi) εἶς, ἐσσί (eis, essi) ἐστί(ν) (esti(n)) εἰμέν (eimen) ἐστέ (este) εἰσί(ν), ἔασι (eisi(n), easi) | εἰμί (eimi) εἶ (ei) ἐστί(ν) (esti(n)) ἐσμέν (esmen) ἐστέ (este) εἰσί(ν) (eisi(n)) | είμαι (ime) είσαι (ise) είναι (ine) είμαστε (imaste) είστε (iste) είναι (ine) |
| Preterite indicative | 1st sg. 2nd sg. 3rd sg. 1st pl. 2nd pl. 3rd pl. | ἦα, ἔον (ēa, eon) ἦσθα, ἔησθα (ēstha, eēstha) ἦ(ε)ν, ἔην (ē(e)n, eēn) ἦμεν (ēmen) ἦτε (ēte) ἦσαν (ēsan) | ἦ(ν) (ē(n)) ἦς, ἦσθα (ēs, ēstha) ἦν (ēn) ἦμεν (ēmen) ἦστε, ἔατε (ēste, eate) ἦσαν ἔσαν (ēsan, esan) | ήμουν (imun) ήσουν (isun) ήταν (itan) ήμασταν (imaste, imastan) ήσασταν (isaste, isastan) ήταν, (ήσαν) (itan, (isan)) |
| Subjunctive | 1st sg. 2nd sg. 3rd sg. 1st pl. 2nd pl. 3rd pl. | ἔω (eō) ἔῃς, ἔοις (eēis, eois) ἔῃ(σι), ᾖσι(ν), ἔοι (eēi(si), ēisi(n), eoi)  ἔωσι(ν) (eōsi(n)) | ὦ (ō) ᾖς (ēis) ᾖ (ēi) ὦμεν (ōmen) ἦτε (ēte) ὦσι(ν) (ōsi(n)) | |
| Optative | 1st sg. 2nd sg. 3rd sg. 1st pl. 2nd pl. 3rd pl. | εἴην (eiēn) εἴης (eiēs) εἴη (eiē) εἶτε (eite) εἶεν (eien) | εἴην (eiēn) εἴης (eiēs) εἴη (eiē) εἴημεν, εἶμεν (ei(ē)men) εἴητε, εἶτε (ei(ē)te) εἴησαν, εἶεν (eiēsan, eien) | |
| Imperative | 2nd sg. 3rd sg. 2nd pl. 3rd pl. | ἔσσο, ἴσθι (esso, isthi) ἔστε (este) | ἴσθι (isthi) ἔστω (estō) ἔστε (este) ἔστων, ὄντων (estōn, ontōn) | να είσαι (na ise) να είστε (na iste) |
| Infinitive | | εἶναι, ἔμ(μ)εν(αι) (einai, em(m)en(ai)) | εἶναι (einai) | |
| Participle | | ἐών, ἐόντ- (eōn, eont-) fem. ἐοῦσα (eousa) | ὦν, ὄντ- (ōn, ont-) fem. οὖσα (ousa) | όντας (ontas) |
Dual is not shown in the table.
The participles are based on the full-grade stem ἐσ- in Homeric, according to Smyth.

### Italic languages

Except for Latin, the older Italic languages are very scarcely attested, but we have in Oscan set (they are), fiiet (they become), fufans (they have been) and fust (he will be), and in Umbrian sent (they are). This section will explain Latin, and the Romance languages that have evolved from it.
Esse and the forms beginning with (e)s- are from the root *h$_1$es-, while the forms beginning with f- are from the root *bʰuH-. For the forms beginning with er-, see *h₁er-. Stāre is derived from the root *steh$_2$-.
In Spanish, Catalan, Galician-Portuguese and to a lesser extent, Italian there are two parallel paradigms, ser/èsser/essere from Latin esse "to be" on the one hand, and estar/stare from Latin stare, "to stand" on the other.
In several modern Romance languages, the perfect is a compound tense formed with the past participle as in English, but the old Latin perfect survives as a commonly used preterite in Spanish and Portuguese, and as a literary "past historic" in French, Italian and Catalan.
There is a tendency for a past participle derived from stare (or more specifically its supine, statum) to replace that of the main copula derived from esse. For example, the French participle été comes from statum.
| | | Latin | Latin | Old French | Old French | French | Spanish | Spanish | Italian | Italian | Portuguese | Portuguese | Catalan | Catalan | Romanian | Sicilian | Sicilian | Occitan |
| Infinitive | Infinitive | esse | stāre | estre | ester | être | ser | estar | essere | stare | ser | estar | ser, ésser | estar | a fi, fire | siri | stari | estre,èsser |
| Indicative | Present | sum es est sumus estis sunt | stō stās stat stāmus stātis stant | suis es est sommes estes sont | este estes este estons estez estent | suis es est sommes êtes sont | soy eres/sos es somos sois son | estoy estás está estamos estáis están | sono sei è siamo siete sono | sto stai sta stiamo state stanno | sou és é somos sois são | estou estás está estamos estais estão | sóc ets és som sou són | estic estàs està estem esteu estan | sunt eşti este suntem sunteţi sunt | sugnu sì esti simu siti sù | staiu stai sta stamu stati stannu | soi sès es sèm sètz son |
| Indicative | Preterite | fuī fuistī fuit fuimus fuistis fuērunt/fuēre | stetī stetistī stetit stetimus stetistis stetērunt/stetēre | fui fus fu fumes fustes furent | estai estas esta estames estastes esterent | fus fus fut fûmes fûtes furent | fui fuiste fue fuimos fuisteis fueron | estuve estuviste estuvo estuvimos estuvisteis estuvieron | fui fosti fu fummo foste furono | stetti stesti stette stemmo steste stettero | fui foste foi fomos fostes foram | estive estiveste esteve estivemos estivestes estiveram | fui fores fou fórem fóreu foren | estiguí estugueres estigué estiguérem estiguéreu estigueren | fusei/fui fuseși/fuși fuse/fu fuserăm/furăm fuserăți/furăți fuseră/fură | fui fusti fu fumu fùstivu furu | stesi stasti stesi stèsimu stàsivu stèsiru | foguèri foguères foguèt foguèrem foguèretz foguèron |
| Indicative | Imperfect | eram erās erat erāmus erātis erant | stābam stābās stābat stābāmus stābātis stābant | ier iers iert iermes seroiz ierent | estoie estoies estoit estiens estiez estoient | étais étais était étions étiez étaient | era eras era éramos erais eran | estaba estabas estaba estábamos estabais estaban | ero eri era eravamo eravate erano | stavo stavi stava stavamo stavate stavano | era eras era éramos éreis eram | estava estavas estava estávamos estaveis estavam | era eres era érem éreu eren | estava estaves estava estàvem estàveu estaven | eram erai era eram erați erau | era eri era èramu èravu èranu | stava stavi stava stàvamu stàstivu stàvanu | èri èras èra èram èratz èran |
| Indicative | Pluperfect | fueram fuerās fuerat fuerāmus fuerātis fuerant | steteram steterās steterāt steterāmus steterātis steterant | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | fora foras fora fôramos fôreis foram | estivera estiveras estivera estivéramos estivéreis estiveram | - - - - - - | - - - - - - | fusesem fuseseși fusese fuseserăm fuseserăți fuseseră | - - - - - - | - - - - - - | - - - - - - |
| Indicative | Future | erō eris/ere erit erimus eritis erunt | stābō stābis stābit stābimus stābitis stabunt | serai seras sera serons serez seront | esterai | serai seras sera serons serez seront | seré serás será seremos seréis serán | estaré estarás estará estaremos estaréis estarán | sarò sarai sarà saremo sarete saranno | starò starai starà staremo starete staranno | serei serás será seremos sereis serão | estarei estarás estará estaremos estareis estarão | seré seràs serà serem sereu seram | estaré estaràs estarà estarem estareu estaran | voi fi vei fi va fi vom fi veți fi vor fi | - - - - - - | - - - - - - | serai seràs serà serem seretz seràn |
| Indicative | Future Perfect | fuerō fueris fuerit fuerimus fueritis fuerint | steterō steteris steterit steterimus steteritis steterint | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - |
| Subjunctive | Present | sim sīs sit sīmus sītis sint | stem stēs stet stēmus stētis stent | soie soies soit soions soiiez soient | estoise estoises estoise estons estez estoisent | sois sois soit soyons soyez soient | sea seas sea seamos seáis sean | esté estés esté estemos estéis estén | sia sia sia siamo siate siano | stia stia stia stiamo stiate stiano | seja sejas seja sejamos sejais sejam | esteja estejas esteja estejamos estejais estejam | sigui/siga siguis/sigues sigui/siga siguem sigueu siguin/siguen | estigui/estiga estiguis/estugues estugui/estiga estiguem estigueu estiguin/estiguen | să fiu să fii să fie să fim să fiți să fie | fussi fussi fussi fùssimu fùssivu fùssiru | stassi stassi stassi stàssimu stàssivu stàssiru | siá siás siá siam siatz sián |
| Subjunctive | Imperfect | essem/forem essēs/forēs esset/foret essēmus/forēmus essetis/forētis essent/forent | stārem stārēs stāret stārēmus stārētis stārent | fusse fusses fust fussons fussiez fussent | esteüsse esteüsses esteüst esteüssons esteüssoiz esteüssent | fusse fusses fût fussions fussiez fussent | fuera/fuese fueras/fueses fuera/fuese fuéramos/fuésemos fuerais/fueseis fueran/fuesen | estuviera/estuviese estuvieras/estuvieses estuviera/estuviese estuviéramos/estuviésemos estuvierais/estuvieseis estuvieran/estuviesen | fossi fossi fosse fossimo foste fossero | stessi stessi stesse stessimo steste stessero | fosse fosses fosse fôssemos fôsseis fossem | estivesse estivesses estivesse estivéssemos estivésseis estivessem | fos fossis fos fóssim/fóssem fóssiu/fósseu fossin/fossen | estigués estiguessis estigués estiguéssim/estiguéssem estiguéssiu/estiguésseu estiguessin/estiguessen | să fi fost să fi fost să fi fost să fi fost să fi fost să fi fost | fussi fussi fussi fùssimu fùssivu fùssiru | stassi stassi stassi stàssimu stàssivu stàssiru | foguèsse foguèsses foguèsse foguèssem foguèssetz foguèsson |
| Subjunctive | Future | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | fuere fueres fuere fuéremos fuereis fueren | estuviere estuvieres estuviere estuviéremos estuviereis estuvieren | - - - - - - | - - - - - - | for fores for formos fordes forem | estiver estiveres estiver estivermos estiverdes estiverem | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - |
| Conditional | Conditional | - - - - - - | - - - - - - | seroie seroies seroit seriens seriez seroient | esteroie esteroies esteroit esteriiens esteriiez esteroient | serais serais serait serions seriez seraient | sería serías sería seríamos seríais serían | estaría estarías estaría estaríamos estaríais estarían | sarei saresti sarebbe saremmo sareste sarebbero | starei staresti starebbe staremmo stareste starebbero | seria serias seria seríamos seríeis seriam | estaria estarias estaria estaríamos estaríeis estariam | seria/fóra series/fores seria/fóra seríem/fórem seríeu/fóreu serien/foren | estaria estaries estaria estaríem estaríeu estarien | aș fi ai fi ar fi am fi ați fi ar fi | fora fori fora fòramu fòravu fòranu | - - - - - - | - - - - - - |
| Imperative | Present | - es - - este - | - stā - - stāte - | - soies - soiiens soiiez - | - esta - estons estez - | - sois - soyons soyez - | - sé - seamos sed/sean - | - está - estemos estad/estén - | - sii - - siate - | - sta - - state - | - sê - - sede - | - está - - estai - | - sigues - - sigueu/sigau - | - estigues - - estigueu/estigau - | - fii - - fiți - | - sì - - siti - | - stai - - stati - | - siá - siam siatz - |
| Imperative | Future | - estō estō - estōte suntō | - stātō stātō - stātōte stantō | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - | - - - - - - |
| Past participle | Past participle | fuisse | statum | esté | esté | été | sido | estado | stato/essuto | stato | sido | estado | estat/sigut/sét | estat | fost | statu | statu | estat, estada |
| Present Participle | Present Participle | esse | stāns | estant | estant | étant | siendo | estando | essendo | stando | sendo | estando | sent/essent | estant | fiind | sennu | sannu | essent |
| | | Latin | Latin | Old French | Old French | French | Spanish | Spanish | Italian | Italian | Portuguese | Portuguese | Catalan | Catalan | Romanian | Sicilian | Sicilian | Occitan |

### Germanic languages

The proto-Germanic verb for 'to be', *wesaną, and its conjugations are mostly derived from the Proto-Indo-European verb *h$_2$wes (‘stay overnight, camp’). The present subjunctive stem is derived from the optative of *h$_1$es-. West Germanic languages also have an additional stem *bi- (such as 'to be' in English), which is thought to derive from the PIE stem *bʰuh₂- ('become'). Proto-Germanic retained the dual, but only in the first and second person.
| | Proto-Germanic (reconstructed) | Proto-Germanic (reconstructed) | Gothic | Old Norse | Icelandic | Faroese | Norwegian Nynorsk | Norwegian Bokmål + Danish | Norwegian Bokmål + Danish | Old Swedish | Swedish | Old English | Old English | English | Old High German | German | Luxem- burgish | Old Saxon | Dutch |
| Infinitive | *wesaną | *beuną? | wisan | vera | vera | vera | vera/vere | være | være | vara | vara | wesan | bēon | be | wesan | sein | sinn | wesan | zijn/wezen |
| Present indicative | *immi *izi *isti *izū *izudiz *izum *izud *sindi | *biumi *biusi *biuþi *beū? *biuþiz *beum *beuþ *biunþi | im is ist siju sijuts sijum sijuþ sind | em ert (est) er (es) – – erum eruð eru | er ert er – – erum eruð eru | eri ert er – – eru eru eru | er er er – – er er er | er er er – – er er er | er er er – – er er er | æm/ær æst ær – – ærum ærin æru | är (äm) är (äst) är – – är (äro) är (ären) är (äro) | eom eart is – – sint sint sint | bēo bist biþ – – bēoþ bēoþ bēoþ | am art is – – are are are | bim, bin bist ist – – birum, bir(e)n birut, bir(e)t sint | bin bist ist – – sind seid sind | si(nn) bass ass – – si(nn) sidd si(nn) | bium bist is – – sind sind sind | ben – is – – zijn bent/zijt* zijn |
| Present subjunctive | *sijǭ *sijēs *sijē *sīw *sīþiz *sīm *sīþ *sīn | *biwjǭ? *biwjēs? *biwjē? *biwīw *biwīþiz *biwīm *biwīþ *biwīn | sijau sijais sijai sijaiwa sijaits sijaima sijaiþ sijaina | sjá sér sé – – sém séð sé | sé sért sé – – séum séuð séu | veri veri veri – – veri veri veri | – – (vere) – – – – – | – – (være) – – – – – | – – (være) – – – – – | – – sē(i)/vari – – – – sēi(n)/vari(n) | – – (vare) – – – – – | sīe sīe sīe – – sīen sīen sīen | bēo bēo bēo – – bēon bēon bēon | be be be – – be be be | sī sīs(t) sī – – sīm, sīn sī(n)t sīn | sei sei(e)st sei – – seien seiet seien | – – sief – – – – – | sī sīs(t) sī – – sīn sīn sīn | zij – zij – – zijn zij zijn |
| Preterite indicative | *was *wast *was *wēzū *wēzudiz *wēzum *wēzud *wēzun | *was *wast *was *wēzū *wēzudiz *wēzum *wēzud *wēzun | was wast was wēsu wēsuts wēsum wēsuþ wēsun | var varst var – – várum várið váru | var varst var – – vorum voruð voru | var vart var – – vóru vóru vóru | var var var – – var var var | var var var – – var var var | var var var – – var var var | var vast var – – vārum vārin vāru | var var var – – var (voro) var (voren) var (voro) | wæs wǣre wæs – – wǣron wǣron wǣron | wæs wǣre wæs – – wǣron wǣron wǣron | was wast was – – were were were | was wāri was – – wārum wārut wārun | war warst war – – waren wart waren | war waars war – – ware(n) waart ware(n) | was wāri was – – wārun wārun wārun | was – was – – waren was/waart* waren |
| Preterite subjunctive | *wēzį̄ *wēzīz *wēzī *wēzīw *wēzīdiz *wēzīm *wēzīd *wēzīn | *wēzį̄ *wēzīz *wēzī *wēzīw *wēzīdiz *wēzīm *wēzīd *wēzīn | wēsjau wēseis wēsi wēseiwa wēseits wēseima wēseiþ wēseina | væra værir væri – – værim værið væri | væri værir væri – – værum væruð væru | væri væri væri – – væri væri væri | – – – – – – – – | var var var – – var var var | var var var – – var var var | – – vāri – – – – vāri(n) | vore vore vore – – vore vore (-en) vore | wǣre wǣre wǣre – – wǣren wǣren wǣren | wǣre wǣre wǣre – – wǣren wǣren wǣren | were wert were – – were were were | wāri wārīs wāri – – wārīm wārīt wārīn | wäre wärest wäre – – wären wäret wären | wier wiers wier – – wiere(n) wiert wiere(n) | wāri wāris wāri – – wārin wārin wārin | ware – ware – – waren ware waren |
| Imperative | - *wes *wesadau - *wesadiz - *wisid *wesandau | - *wes *wesadau - *wesadiz - *wisid *wesandau | - wis wisadau – wisats - wisiþ wisandau | - ver ver – – – verið verið | - vertu vertu – – - verið verið | - ver ver – – - verið verið | – ver ver – – – ver ver | - vær vær – – - vær vær | - vær vær – – - vær vær | – - - – – – – - | - var var – – - var var | - wes wes – – - wesaþ wesaþ | - wes wes – – - wesaþ wesaþ | - be be – – - be be | - wes wes – – - wesit wesit | - sei sei – – - seid seid | - - - – – - - - | - wes wes – – - wesad wesad | - wees - – – - weest - |
| Past participle | – | – | – | verit | verið | verið | vore (vori) | vært | været | varin | varit | – | – | been | giwesan | gewesen | gewiescht | (gi)wesan | geweest |
* Old English kept the verbs wesan and bēon separate throughout the present stem, though it is not clear that the kind of consistent distinction in usage was made that we find, for example in Spanish. In the preterite, however, the paradigms fell together. Old English has no participle for this verb.
* The plural forms in Modern Swedish (indicated in brackets) were in common use in formal written language until the mid-20th century, but are now no longer in use except in deliberately archaising texts. The preterite subjunctive is also increasingly being replaced by the indicative, or past participle.
* Dutch, like English, has abandoned the original second-person singular forms, replacing them with the second-person plural forms. However, while in English the old forms are still in limited and deliberately archaic use, in Dutch they have disappeared entirely and are no longer known or used at all. The forms listed in the plural are the historical plural forms, the 'jij' and 'gij' forms. Dutch formed a new plural pronoun 'jullie' with inflection similar to the 1st and 3rd person plural, but it would be redundant to list them here.

### Slavic languages

| | Proto-Slavic (reconstructed) | Old Church Slavonic | Ukrainian | Russian | Old Polish | Polish | Czech | Slovak | Slovenian | Serbo-Croatian | Bulgarian |
| Present | *(j)esmĭ *(j)esi *(j)estĭ *(j)esvě *(j)esta *(j)este *(j)esmŭ *(j)este *sǫtĭ | ѥсмь, jesmĭ ѥси, jesi ѥстъ, jestŭ ѥсвѣ, jesvě ѥста, jesta ѥсте, jeste ѥсмъ, jesmŭ ѥсте, jeste сѫтъ, sǫtŭ | (є[сь]м, je[ś]m) (єси, jesy) є, je /{єсть, jesť} – – – ((є)сьмо, (je)śmo) ((є)сте, (je)ste) (суть, suť) | (есмь, jesm') (еси, jesi) есть, jest' – – – (есмо, jesmo) (есте, jeste) (суть, sut') | jeśm jeś jest, jeść – – – jeśmy jeście są | jestem, -m jesteś, -ś jest – – – jesteśmy, -śmy jesteście, -ście są | jsem jsi je – – – jsme jste jsou | som si je – – – sme ste sú | sem si je sva sta sta smo ste so | jesam, sam/budem* jesi, si/budeš jest, je/bude – – – jesmo, smo/budemo jeste, ste/budete jesu, su/budu | съм, səm си, si е, e – – – сме, sme сте, ste са, sə |
| Imperative | – *bǫdi *bǫdi *bǫděvě *bǫděta – *bǫděmŭ *bǫděte *bǫdǫ | – бѫди, bǫdi бѫди, bǫdi бѫдѣвѣ, bǫděvě бѫдѣта, bǫděta – бѫдѣмъ, bǫděmŭ бѫдѣте, bǫděte бѫдѫ, bǫdǫ | – будь, buď – – – – будьмо, buďmo будьте, buďte – | – будь, bud’ – – – – – будьте, bud’te – | – bądź – – – – bądźmy bądźcie – | – bywaj/bądź – – – – bywajmy/bądźmy bywajcie/bądźcie – | – buď – – – – buďme buďte – | – buď – – – – buďme buďte – | – bodi – bodiva bodita – bodimo bodite – | – budi (neka bude) – – – budimo budite (neka budu) | – бъди, bədi – – – – – бъдете, bədete – |
| Future | *bǫdǫ *bǫdešĭ *bǫdetĭ *bǫdevě *bǫdeta *bǫdete *bǫdemŭ *bǫdete *bǫdǫtĭ | бѫдѫ, bǫdǫ бѫдеши, bǫdeši бѫдетъ, bǫdetŭ бѫдевѣ, bǫdevě бѫдета, bǫdeta бѫдете, bǫdete бѫдемъ, bǫdemŭ бѫдете, bǫdete бѫдѫтъ, bǫdǫtŭ | буду, budu будеш, budeš буде, bude – – – будемо, budemo будете, budete будуть, buduť | буду, budu будешь, budeš' будет, budet – – – будем, budem будете, budete будут, budut | będę będziesz będzie – – – będziemy będziecie będą | będę będziesz będzie – – – będziemy będziecie będą | budu budeš bude – – – budeme budete budou | budem budeš bude – – – budeme budete budú | bom, bodem boš, bodeš bo, bode bova, bodeva bosta, bodesta bosta, bodesta bomo, bodemo boste, bodeste bodo, bojo | budem budeš bude – – – budemo budete budu | ще бъда, šte bədə ще бъдеш, šte bədeš ще бъде, šte bəde – – – ще бъдем, šte bədem ще бъдете, šte bədete ще бъдат, šte bədət |
| Imperfect | *běaxŭ *běaše *běaše *běaxově *běašeta *běašete *běaxomŭ *běašete *běaxǫ | бѣахъ, běaxŭ бѣаше, běaše бѣаше, běaše бѣаховѣ, běaxově бѣашета, běašeta бѣашете, běašete бѣахомъ, běaxomŭ бѣашете, běašeте бѣахѫ, běaxǫ | | | biech biesze biesze – – – biechom bieszecie biechą | | | | | bijah, b(j)eh bijaše, b(j)eše bijaše, b(j)eše – – – bijasmo, b(j)esmo bijaste, b(j)este bijahu, b(j)ehu | бях, bjah бе[ше], be[še] бе[ше], be[še] – – – бяхме, bjahme бяхте, bjahte бяха, bjahə |
| Aorist | *byxŭ *by(stŭ?) *by(stŭ?) *byxově *bysta *byste *byxomŭ *byste *byšę | бꙑхъ, byxŭ бꙑ(стъ), by(stŭ) бꙑ(стъ) by(stŭ) бꙑховѣ, byxově бꙑста, bysta бꙑсте, byste бꙑхомъ, byxomŭ бꙑсте, byste бꙑшѧ, byšę | | | bych by by – – – bychom byście bychą | | | | | | |
| Conditional copula | | | | | | bym byś by – – – byśmy byście by | bych bys by – – – bychom byste by | | (bi) bi bi (bi) (bi) (bi) (bi) (bi) (bi) | bih bi bi – – – bismo biste biše | бих, bih би, bi би, bi – – – бихме, bihme бихте, bihte биха, bihə |
| Present active participle | *sy m. *sǫťi f. *sy n. | сꙑ, sy m. сѫщи, sǫšti f. сꙑ, sy n. | | | sący m. sąca f. sące n. | | jsoucí | | | | (същ, səšt m.) (съща, səšta f.) (също, səšto n.) |
| Future active participle | *bǫdy m. *bǫdǫťi f. *bǫdy n. | бѫдꙑ, bǫdy m. бѫдѫщи, bǫdǫšti f. бѫдꙑ, bǫdy n. | | будущий, buduščij m. будущая, buduščaja f. будущее, buduščeje n. | będący m. będąca f. będące n. | będący m. będąca f. będące n. | budoucí m. budoucí f. budoucí n. | budúci m. budúca f. budúce n. | bodoči m. bodoča f. bodoče n. | budući m. buduća f. buduće n. | (бъдещ, bədešt m.) (бъдещa, bədeštа f.) (бъдещо, bədeštо n.) |
| Present gerund | | | будучи | | sąc będąc | będąc | jsa jsouc jsouce | | | | бъдейки |
| Past active participle | *byvŭ m. *byvŭši f. *byvŭ n. | бꙑвъ, byvŭ m. бꙑвъши, byvŭši f. бꙑвъ, byvŭ n. | | бывший, byvšij m. бывшая, byvšaja f. бывшее, byvšeje n. | bywszy m. bywsza f. bywsze n. | bywszy m. bywsza f. bywsze n. | | byvší m. byvšia f. byvšie n. | bivši m. bivša f. bivše n. | bivši m. bivša f. bivše n. | (бивш, bivš m.) (бивша, bivša f.) (бивше, bivše n.) |
| Past gerund | | | бувши | | bywszy | bywszy | byv byvši byvše | | | | - |
| Resultative participle | *bylŭ m. *byla f. *bylo n. | бꙑлъ, bylŭ m. бꙑла, byla f. бꙑло, bylo n. | був, buw m. була, bula f. було, bulo n. | был, byl m. была, byla f. было, bylo n. | był m. była f. było n. | był m. była f. było n. | byl m. byla f. bylo n. | bol m. bola f. bolo n. | bil m. bila f. bilo n. | bio m. bila f. bilo n. | бил, bil m. била, bila f. било, bilo n. |
| Verbal or deverbal noun | *bytĭje | бꙑтиѥ, bytije | буття́, buttja | бытьё, bytʹjó | bycie | bycie | bytí | bytie | bītje | biće | - |
| Infinitive | *byti | бꙑти, byti | бути, buty | быть, byt' | być | być | být | byť | biti | biti | - |
| Supine | - | - | - | - | - | - | - | - | bit | - | - |
* In Russian, the present forms are archaic and no longer in common use, except for the third person forms, which are used in "there is/are" type phrases.
* In Ukrainian, the present tense forms of the verb "бути" have all but disappeared from contemporary language, except for the third person form which is used in existential phrases; єсть (jesť) is archaic and encountered only in poetry. All participles have turned into other parts of speech, future and past active participles becoming present and past active adverbial participle respectively, and resultative pariciple becoming past tense of verbs.
* In Serbo-Croatian the forms jesam, jesi, jeste and so on are used as the basic form of the Present Tense "to be" (i.e. I am, you are etc.), while the forms budem, budeš, bude etc. are used only for the formation of the Future Perfect.
* In Bulgarian, forms бъда, бъдеш, etc. are not used by themselves but only in compound forms (future ще бъда, subjunctive да бъда). In this respect they closely follow the usage (and non-usage) of perfective verbs. As such it has its own forms for the aorist (бидох, биде, биде, бидохме, бидохте, 'бидоха), the imperfect (бъдех, бъдеше, бъдеше, бъдехме, бъдехте, бъдеха) and the resultative participle (бъдел). Another verb - бивам with fully regular conjugation type III paradigm - completes an aspect triple: imperfective съм, perfective бъда, secondary imperfective бивам. The perfective aorist has lost its original meaning and is now used only to form the compound conditional mood (бих чел = I would read). All participles except the resultative participle (бил) have lost their function and are now used as regular adjectives with changed meanings (същ = same, бивш = previous, ex-, бъдещ = future).
* In Polish, the present forms, except for jest and są, have turned into suffixes (-m, -ś, -śmy, -ście) used primarily to construct the past tense and the conditional clitic. The modern conjugation comes from attaching these suffixes onto the third person singular form jest.

### Baltic languages

| | Lithuanian | Latvian |
| Infinitive | būti | būt |
| Present | esu, esmi (rare), esmì (obsol.), būnu esì, būni (rare) yra, esti, estì (obsol.), esa (rare), būna esmè (obsol.), esame, būname (rare) estè (obsol.), esate, būnate (rare) yra, esti (rare), esa (rare), būna (rare) | esmu, esu (vernacular) esi ir esam esat ir |
| Past simple | buvau buvai buvo buvome buvote buvo | biju biji bija bijām bijāt bija |
| Past active participle | buvęs (m. sg.) buvusi (f. sg.) buvę (m. pl.) buvusios (f. pl.) | bijis (m. sg.) bijusi (f. sg.) bijuši (m. pl.) bijušas (f. pl.) |
| Future | būsiu būsi bus būsime būsite bus | būšu būsi būs būsim būsiet, būsit būs |
| Imperative | – būk – būkime būkite – | – esi – būsim esiet – |
| Quotative | | esot, būšot |
| Conditional | būčiau būtum būtų būtumėme būtumėte būtų | būtu |
In Lithuanian, the paradigm būnu, būni, būna, etc. is not considered archaic or dialectal but rather a special use of the verb būti, to be, mostly used to describe repeated actions or states, or habits.

### Celtic languages

In the Celtic languages there is a distinction between the so-called substantive verb, used when the predicate is an adjective phrase or prepositional phrase, and the so-called copula, used when the predicate is a noun.
The conjugation of the Old Irish and Middle Welsh verbs is as follows:
| | Old Irish substantive verb | Old Irish copula | Middle Welsh |
| Present | (at)·tó (at)·taí (at)·tá (at)·taam (at)·taïd (at)·taat | am at is ammi adib it | wyf wyt yw, mae, taw, oes ym ych ynt, maen(t) |
| Preterite | ·bá ·bá ·boí ·bámmar ·baid ·bátar | basa basa ba bommar unattested batar | buum buost bu buam buawch buant |
| Future | bia bie bieid, ·bia beimmi, ·biam bethe, ·bieid bieit, ·biat | be be bid bimmi unattested bit | bydaf bydy byd bydwn bydwch bydant |
The forms of the Old Irish present tense of the substantive verb, as well as Welsh taw, come from the PIE root *stā-. The other forms are from the roots *es- and *bhū-. Welsh mae originally meant "here is" (cf. yma 'here').

#### Irish and Scottish Gaelic

In modern Gaelic, person inflections have almost disappeared, but the negative and interrogative are marked by distinctive forms. In Irish, particularly in the south, person inflections are still very common for the tá/bhí series.

##### The verb bí

| | | Scottish Gaelic | Irish | Irish | Irish |
| | | Scottish Gaelic | (analytic) | (synthetic) | (synthetic) |
| Present | affirmative | tha | tá | 1 táim, 2 †táir, 3 tá, 1pl táimíd, 2pl †táthaoi, 3pl táid | 1 táim, 2 †táir, 3 tá, 1pl táimíd, 2pl †táthaoi, 3pl táid |
| Present | negative | chan eil | níl (< ní fhuil) | 1 nílim, 2 †nílir, 3 níl, 1pl nílimíd, 2pl †níltí, 3pl nílid | 1 nílim, 2 †nílir, 3 níl, 1pl nílimíd, 2pl †níltí, 3pl nílid |
| Present | interrogative | a bheil | an bhfuil | 1 an bhfuilim, 2 †an bhfuilir, 3 an bhfuil, 1pl an bhfuilimíd, 2pl †an bhfuiltí, 3pl an bhfuilid | 1 an bhfuilim, 2 †an bhfuilir, 3 an bhfuil, 1pl an bhfuilimíd, 2pl †an bhfuiltí, 3pl an bhfuilid |
| Present | negative interrogative | nach eil | nach bhfuil | 1 nach bhuilim, 2 †nach bhfuilir, 3 nach bhfuil, 1pl nach bhfuílimíd, 2pl †nach bhfuiltí, 3pl nach bhfuilid | 1 nach bhuilim, 2 †nach bhfuilir, 3 nach bhfuil, 1pl nach bhfuílimíd, 2pl †nach bhfuiltí, 3pl nach bhfuilid |
| Past | affirmative | bha | bhí | 1 bhíos, 2 bhís, 3 bhí, 1pl bhiomair, 2pl bhíobhair, 3pl bhíodar | 1 bhíos, 2 bhís, 3 bhí, 1pl bhiomair, 2pl bhíobhair, 3pl bhíodar |
| Past | negative | cha robh | ní raibh | ní | 1 rabhas, 2 rabhais, 3 raibh, 1pl rabhamair, 2pl rabhabhair, 3pl rabhadar |
| Past | interrogative | an robh | an raibh | an | 1 rabhas, 2 rabhais, 3 raibh, 1pl rabhamair, 2pl rabhabhair, 3pl rabhadar |
| Past | negative interrogative | nach robh | nach raibh | nach | 1 rabhas, 2 rabhais, 3 raibh, 1pl rabhamair, 2pl rabhabhair, 3pl rabhadar |
| Future | affirmative | bidh (or "bithidh") | beidh | 1 bead, 2 beir, 3 beidh, 1pl beimíd, 2pl beidh sibh, 3pl beid | 1 bead, 2 beir, 3 beidh, 1pl beimíd, 2pl beidh sibh, 3pl beid |
| Future | negative | cha bhi | ní bheidh | ní | 1 bhead, 2 bheir, 3 bheidh, 1pl bheimíd, 2pl bheidh sibh, 3pl bheid |
| Future | interrogative | am bi | an mbeidh | an | 1 mbead, 2 mbeir, 3 mbeidh, 1pl mbeimíd, 2pl mbeidh sibh, 3pl mbeid |
| Future | negative interrogative | nach bi | nach mbeidh | nach | 1 mbead, 2 mbeir, 3 mbeidh, 1pl mbeimíd, 2pl mbeidh sibh, 3pl mbeid |
† archaic forms
Gaelic (bh)eil and Irish (bh)fuil are from Old Irish fuil, originally an imperative meaning "see!" (PIE root *wel-, also in Welsh gweled, Germanic wlitu- "appearance", and Latin voltus "face"), then coming to mean "here is" (cf. French voici < vois ci and voilà < vois là), later becoming a suppletive dependent form of at-tá. Gaelic robh and Modern Irish raibh are from the perfective particle ro (ry in Welsh) plus ba (lenited after ro).

##### The copula

| | | Scottish Gaelic | | Irish | |
| | | Before a consonant | Before a vowel | Before a consonant | Before a vowel |
| Present | affirmative interrogative negative negative interrogative | is | | is an ní nach | is an ní nach |
| Past/Conditional | affirmative interrogative negative negative interrogative | bu | | ba ar níor nár | b' arbh níorbh nárbh |

#### Modern Welsh

The present tense in particular shows a split between the North and the South. Though the situation is undoubtedly more complicated, King (2003) notes the following variations in the present tense as spoken (not as written according to the standard orthography):
    Affirmative (I am) Interrogative (Am I?) Negative (I am not) Singular Plural Singular Plural Singular Plural North First person dw dan ydw? ydan? (dy)dw (dy)dan Second person —, (r)wyt dach wyt? (y)dach? dwyt (dy)dach Third person mae maen ydy? ydyn? dydy dydyn South First person rw, w ŷn, — ydw? ŷn? (d)w ŷn Second person —, (r)wyt ych wyt? ych? — (ych) Third person mae maen ydy?, yw? ŷn? dyw ŷn
For example, the spoken first person singular dw i'n is a contraction of the formal written yr ydwyf fi yn . The Welsh F /v/ is the fricative analogue of the nasal /m/, the PIE suffix consonant for the first person singular.
    Affirmative (I am) Interrogative (Am I?) Negative (I am not) Singular Plural Singular Plural Singular Plural Preterite First person bues buon fues? fuon? fues fuon Second person buest buoch fuest? fuoch? fuest fuoch Third person buodd buon fuodd? fuon? fuodd fuon Imperfect First person roeddwn roedden oeddwn? oedden? doeddwn doedden Second person roeddet roeddech oeddet? oeddech? doeddet doeddech Third person roedd roeddyn oedd? oeddyn? doedd doeddyn Future First person bydda byddwn fydda? fyddwn? fydda fyddwn Second person byddi byddwch fyddi? fyddwch? fyddi fyddwch Third person bydd byddan fydd? fyddan? fydd fyddan
Bod also has a conditional, for which there are two stems. The bas- stem is more common in the North, and the bydd- stem is more common in the South:
    Affirmative Interrogative Negative Singular Plural Singular Plural Singular Plural bydd- First person byddwn bydden fyddwn fydden fyddwn? fydden? Second person byddet byddech fyddet fyddech fyddet? fyddech? Third person byddai bydden fyddai fydden fyddai? fydden? bas- First person baswn basen faswn fasen faswn? fasen? Second person baset basech faset fasech faset? fasech? Third person basai basen fasai fasen fasai? fasen?

### Hittite

The Hittite verb "to be" is derived from the Indo-European root *h$_1$es-.
| | Present indicative | Preterite indicative | Imperative |
| 1st sg. | ēšmi | ešun | ēšlit ēšlut ašallu |
| 2nd sg. | ēšši | ēšta | ēš |
| 3rd sg. | ēšzi | ēšta | ēšdu |
| 1st pl. | (ašweni) | ēšwen | – |
| 2nd pl. | ēšteni | ēšten | ēšten |
| 3rd pl. | ašanzi | ešer | ašandu |

### Armenian

The Classical Armenian present tense derives from PIE *h₁es- (cf. sg. h₁esmi, h₁essi, h₁esti; 3rd pl. h₁s-énti).
| | present |
| 1st sg. | em |
| 2nd sg. | es |
| 3rd sg. | ē |
| 1st pl. | enkʿ |
| 2nd pl. | ēkʿ |
| 3rd pl. | en |

### Albanian

The Albanian copula shows two distinct roots. The present jam ‘I am’ is an athematic root stem built from PIE *h₁es-. The imperfect continues the PIE imperfect of the same root but was rebuilt based on the 3rd person singular and plural. The preterite, on the other hand, comes from the thematic aorist of PIE *kʷel- ‘turn’ (cf. Ancient Greek épleto ‘he turned’, Armenian eɫew ‘he became’, Old Irish cloïd ‘turns back, defeats’). Analogical or otherwise indirect reflexes are italicized below.
| | PIE | present | PIE → PAlb | rebuilt | imperfect (NE Arvanitic) | imperfect (standard Alb) | PIE → PAlb | preterite |
| 1st sg. | *h₁ésmi | jam | *h₁és-m̥ → *eham | *eśen | jeshë | isha | *kʷl-e-m̥ → *klen$^†$ | qeshë, OAlb qeva |
| 2nd sg. | *h₁ési | je | *h₁és → *eh | *eśeh | jeshe | ishe | *kʷl-e-s → *kleh | qe |
| 3rd sg. | *h₁ésti | ishtë (dial.) ësht (standard) | *h₁és-t → *eśt | *eśt | je | ish → ishte | *kʷl-e-to → *kleta | kle → qe |
| 1st pl. | *h₁s-méi | jemi | *h₁s-m̥é → *emma/e | *eśema/e | jeshëmë | ishim | *kʷl-e-mé → *klema/e | qemë |
| 2nd pl. | *esi (2nd sg.) + -ni | jeni | *h₁s-té → *eśtā | *eśetā | jeshëtë | ishit | *kʷl-e-té → *kletā | qetë |
| 3rd pl. | *h₁s-nti | janë | *h₁s-énd → *eśend | *eśend | ishinë | ishin | *kʷl-e-nd → *klend | qenë |