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, a function which in non-Indo-European languages can be expressed quite differently.
- In a more heavily marked context it expresses existence.
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 tenses. 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.
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
''*h1es-''
The root *h1es- was certainly already a copula in Proto-Indo-European.The e-grade *h1es- 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 *h1s- produces forms beginning with /s/, like German sind, Latin sumus, Vedic Sanskrit smas, etc.
In PIE, *h1es- was an athematic verb in -mi; that is, the first person singular was *h1esmi; 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 | *h1és-mi | *h1és-m̥ | *h1és-oh2 | *h1s-iéh1-m | — |
| 2nd singular | *h1és-i | *h1és | *h1és-esi | *h1s-iéh1-s | *h1és, *h1s-dʰí |
| 3rd singular | *h1és-ti | *h1és-t | *h1és-eti | *h1s-iéh1-t | *h1és-tu |
| 1st dual | *h1s-uós | *h1s-ué | *h1és-owos | *h1s-ih1-wé | — |
| 2nd dual | *h1s-tés | *h1s-tóm | *h1és-etes | *h1s-ih1-tóm | *h1s-tóm |
| 3rd dual | *h1s-tés | *h1s-tā́m | *h1és-etes | *h1s-ih1-tā́m | *h1s-tā́m |
| 1st plural | *h1s-m̥ós | *h1s-m̥é | *h1és-omos | *h1s-ih1-mé | — |
| 2nd plural | *h1s-té | *h1s-té | *h1és-ete | *h1s-ih1-té | *h1s-té |
| 3rd plural | *h1s-énti | *h1s-énd | *h1és-onti | *h1s-ih1-énd | *h1s-éntu |
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 ; Persian imperative bov, past bud and future bâš; and the Slavic infinitive and past, etc. for example Russian быть, был.
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, from which physics and physical are derived.
bʰuH- was a preterite-present verb, i.e. imperfect endings for the present, and can be reconstructed as follows:
| Person | Indicative | Subjunctive | Optative | Imperative |
| 1st singular | *bʰúH-m | *bʰúH-oh2 | *bʰuH-yéh1-m | — |
| 2nd singular | *bʰúH-s | *bʰúH-esi | *bʰuH-yéh1-s | *bʰúH, *bʰuH-dʰí |
| 3rd singular | *bʰúH-t | *bʰúH-eti | *bʰuH-yéh1-t | *bʰúH-tu |
| 1st dual | *bʰuH-wé | *bʰúH-owos | *bʰuH-ih1-wé | — |
| 2nd dual | *bʰuH-tóm | *bʰúH-etes | *bʰuH-ih1-tóm | *bʰuH-tóm |
| 3rd dual | *bʰuH-tā́m | *bʰúH-etes | *bʰuH-ih1-tā́m | *bʰuH-tā́m |
| 1st plural | *bʰuH-mé | *bʰúH-omos | *bʰuH-ih1-mé | — |
| 2nd plural | *bʰuH-té | *bʰúH-ete | *bʰuH-ih1-té | *bʰuH-té |
| 3rd plural | *bʰuH-énd | *bʰúH-onti | *bʰuH-ih1-énd | *bʰuH-éntu |
''*h2wes-''
The root *h2wes- 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 survives in English and Old High German was, while the lengthened e-grade gives us English were. See Germanic strong verb: Class 5.''*h1er-''
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 and future tenses.However, other authorities link these forms with *h1es- and assume grammatischer Wechsel, 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. Furthermore, the third person plural form sindi 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 existed side by side in Germanic, and the involvement of a separate root h₁er- is unnecessary.
The Latin forms could be explained by rhotacism.
''*steh2-''
The root *teh2- 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 use it as one of their two copulae, and there is also a Romance tendency for a past participle derived from *steh2- to replace the original one of the copula. 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. While it is not a full copula, it does have shades of meaning that resemble that of the Italian sto cucinando. The intransitive verbs zitten, liggen and lopen are used in similar ways.
In Swedish, which usually lacks gerund forms, the corresponding stå is often used similarly, along with sitta, ligga and gå.
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-» as well.
The resulting paradigms
Indo-Iranian languages
Indic languages
Sanskrit
The Vedic Sanskrit root as is derived from the Indo-European root *h1es-.bhū is derived from Indo-European *bʰuH-.
Hindi-Urdu
In modern Hindi-Urdu, the Sanskrit verb अस् ' which is derived from the Indo-European root *h1es- has developed into the present indicative forms of the verb होना ہونا '. The infinitive होना ہونا ' itself is derived from the Sanskrit verb root भू ' which is derived from Indo-European root bhuH-. The indicative imperfect forms of होना ہونا ' comes from Sanskrit स्थित ' "standing, situated" which are derived from the PIE root *steh₂-. होना ہونا 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 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 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.