Some languages use copulas differently, so a sentence like "Bob old" would be a complete and grammatical expression, while they might still use a copula to associate one noun with another as in the "fireman" example. The artificial language Lojban has no copula at all, 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. malcitno", and "la bob. fagdirpre". Some languages also have more than one copula for different uses; for example the Spanish language uses the verb "ser" to link a subject to a predicate that specifies an identity or inherent quality ("Bob is old" would be "Bob es viejo"), and the verb "estar" to link predicates that specify a temporary condition ("Bob is here" would be "Bob está aquí").
It should be pointed out that the English verb be can also be used as a standalone predicate when it is used to express mere existence. "I am" is a complete sentence meaning "I exist", and in this case "am" is not a copula but a normal, meaningful verb.
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