Editing Copula (linguistics) (section)

=== Other functions ===
A copular verb may also have other uses supplementary to or distinct from its uses as a copula. Some co-occurrences are common.

==== Auxiliary verb ====
The English verb ''[[wikt:be#Verb|to be]]'' is also used as an [[English auxiliaries|auxiliary verb]], especially for expressing [[passive voice]] (together with the [[past participle]]) or expressing [[progressive aspect]] (together with the [[present participle]]):

{{Poem quote|
The man '''was''' killed. (passive)
It '''is''' raining. (progressive)
}}

Other languages' copulas have additional uses as auxiliaries. For example, French {{lang|fr|être}} can be used to express passive voice similarly to English ''be''; both French {{lang|fr|être}} and German {{lang|de|sein}} are used to express the [[Perfect (grammar)|perfect forms]] of certain verbs:

{{Poem quote|{{lang|fr|Je '''suis''' allé(e)}} French for {{gloss|I went}} and {{gloss|I have gone}}, literally {{gloss|I am gone}}, but does not imply still being gone.}}

In the same way, usage of English ''be'' in the present perfect, though archaic, is still commonly seen in old texts/translations:

{{Poem quote|
I '''am''' become death.
He '''is''' risen.
}}

The auxiliary functions of these verbs derived from their copular function, and could be interpreted as special cases of the copular function (with the verbal forms it precedes being considered adjectival).<!-- This sentence needs revision in order to be readily comprehended. -->

Another auxiliary usage in English is to denote an obligatory action or expected occurrence: "I am to serve you". "The manager is to resign". This can be put also into past tense: "We were to leave at 9". For forms such as "if I was/were to come", see [[English conditional sentences]]. (By certain criteria, the English copula ''be'' may always be considered an auxiliary verb; see [[Auxiliary verb#Diagnostics for identifying auxiliary verbs in English|Diagnostics for identifying auxiliary verbs in English]].)

==== Existential verb ====
The English ''to be'' and its equivalents in certain other languages also have a non-copular use as an existential verb, meaning "to exist". This use is illustrated in the following sentences: ''I want only '''to be''', and that is enough''; ''[[Cogito ergo sum|I think therefore I '''am''']]''; ''[[To be, or not to be|'''To be''' or not '''to be''']], that is the question.'' In these cases, the verb itself expresses a predicate (that of [[existence]]), rather than linking to a predicative expression as it does when used as a copula. In [[ontology]] 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''. However, [[Abelard]] in his ''Dialectica'' made a ''[[reductio ad absurdum]]'' argument against the idea that the copula can express existence.<ref>Kneale – Kneale 1962 and Moro 1997</ref>

Similar examples can be found in many other languages; for example, the French and Latin equivalents of ''I think therefore I am'' are {{lang|fr|Je pense, donc je '''suis'''}} and {{lang|la|Cogito ergo '''sum'''}}, where {{lang|fr|suis}} and {{lang|la|sum}} are the equivalents of English "am", normally used as copulas. However, other languages prefer a different verb for existential use, as in the Spanish version {{lang|es|Pienso, luego '''existo'''}} (where the verb {{lang|es|existir}} {{gloss|to exist}} is used rather than the copula {{lang|es|ser}} or {{lang|es|estar}} {{gloss|to be}}).

Another type of existential usage is in clauses of the ''[[there is]]...'' or ''there are...'' type. Languages differ in the way they express such meanings; some of them use the copular verb, possibly with an [[expletive pronoun]] such as the English ''there'', while other languages use different verbs and constructions, such as the French {{lang|fr|il y a}} (which uses parts of the verb {{lang|fr|avoir}} {{gloss|to have}}, not the copula) or the Swedish {{lang|sv|finns}} (the passive voice of the verb for "to find"). For details, see [[existential clause]].

Relying on a unified theory of copular sentences, it has been proposed that the English ''there''-sentences are subtypes of [[inverse copular construction]]s.<ref>See Moro 1997, and "existential sentences and expletive ''there''" in Everaert et al. 2006, for a detailed discussion of this issue and a historical survey of the major proposals.</ref>