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This page pertains to UD version 2.

cop: copula

A cop (copula) is the relation of a function word used to link a subject to a nonverbal predicate, including the expression of identity predication (e.g. sentences like “Kim is the President”). It is often a verb but nonverbal (pronominal) copulas are also frequent in the world’s languages. Verbal copulas are tagged AUX, not VERB. Pronominal copulas are tagged PRON or DET.

The cop relation should only be used for pure copulas that add at most TAME categories to the meaning of the predicate, which means that most languages have at most one copula, and only when the nonverbal predicate is treated as the head of the clause.

As a concrete example, in many European languages the equivalent of the English verb to be is the only word that can appear with the cop relation. In Spanish and related languages, both ser and estar can be copulas. In Czech and related languages, both být and bývat are copulas (because they are morphological variants of the same lexeme, and the reason they have two lemmas is that aspect-related morphology is treated as derivational in these languages). In contrast, the equivalents of to become are not copulas despite the fact that traditional grammar may label them as such. Existential to be can be copula only if it is the same verb as in equivalence clauses (John is a teacher). If a language uses two different verbs, then the existential one is not a copula. Some more discussion of the topic is archived here.

Bill is honest
nsubj(honest, Bill)
cop(honest, is)
Ivan is the best dancer
nsubj(dancer-5, Ivan-1)
cop(dancer-5, is-2)
det(dancer-5, the-3)
amod(dancer-5, best-4)

The copula be is not treated as the head of a clause, but rather the nonverbal predicate, as exemplified above.

Such an analysis is motivated by the fact that many languages often or always lack an overt copula in such constructions, as in the the following Russian and Hebrew examples:

Ivan lučšij tancor \n Ivan best dancer
nsubj(tancor, Ivan)
amod(tancor, lučšij)
ani Kim \n I am Kim
nsubj(Kim-2, ani-1)

In informal English, this may also arise.

Email usually free if you have Wifi.
nsubj(free, Email)

This analysis is adopted also when the predicate is a prepositional phrase, provided that the same copula (or absence thereof) is used here, in which case the nominal part of the prepositional phrase is the head of the clause.

Sue is in shape
nsubj(shape, Sue)
cop(shape, is)
case(shape, in)

If the copula is accompanied by other verbal auxiliaries for tense, aspect, etc., then they are also given a flat structure, and taken as dependents of the lexical predicate:

Sue has been helpful
nsubj(helpful, Sue)
cop(helpful, been)
aux(helpful, has)

The motivation for this choice is that this structure is parallel to the flat structure which we give to auxiliary verbs accompanying verbs. In particular, in languages such as English, it is often very difficult to decide whether to regard a participle as a verb or an adjective. Perhaps the following sentence is such a case:

The presence of troops will be destabilizing .
nsubj(destabilizing, presence)
cop/aux(destabilizing, be)
aux(destabilizing, will)

While a part of speech (and associated deprel: cop vs. aux) has to be decided in such cases, it would be unfortunate if the choice of part of speech also changed the dependency structure. Note, however, that the exact distribution of the copula construction is subject to language-specific variation.

Finally, the cop relation is not used when the nonverbal predicate has the form of a clause, which typically occur in equational constructions like the following:

The important thing is to keep calm .
ccomp(is, keep)
nsubj(is, thing)
The problem is that this has never been tried .
ccomp(is, tried)
nsubj(is, problem)

If we took the predicate of the clause as the head, instead of the copula verb, it would have two subjects, which would be unworkable. Examples like the above could be analyzed reversed with the initial noun phrase as the predicate, but in addition to this seeming undesirable, it would fail to be a solution if there were a clause on both sides of be, such as in: (For us) to not attempt to solve the problem is (for us) to acknowledge defeat. (Note: This solution is not perfect and refining it is a possible direction for the future.)


cop in other languages: [bej] [bg] [cop] [cs] [de] [el] [en] [es] [et] [eu] [fi] [fo] [fr] [fro] [ga] [gsw] [hy] [id] [it] [ja] [kk] [kpv] [myv] [no] [pcm] [pt] [ro] [ru] [sv] [swl] [tr] [u] [urj] [vi] [yue] [zh]