valency (n.)

A term introduced by the French linguist Lucien Tesnière (1893– 1954), which has been particularly influential in the development of models of DEPENDENCY GRAMMAR in Europe and Russia. The term is derived from chemistry, and is used in LINGUISTICS to refer to the number and type of bonds which SYNTACTIC ELEMENTS may form with each other; this ‘combining capacity’ is also known as adicity or arity. As in chemistry, a given element may have different valencies in different contexts. A valency grammar presents a MODEL of a SENTENCE containing a fundamental element (typically, the VERB) and a number of dependent elements (variously referred to as ARGUMENTS, expressions, COMPLEMENTS or valents) whose number and type is determined by the valency attributed to the verb. For example, the valency of vanish includes only the SUBJECT element (it has a valency of 1, monovalent, or monadic), whereas that of scrutinize includes both subject and DIRECT OBJECT (a valency of 2, bivalent, or dyadic). Verbs which take more than two complements are polyvalent, or polyadic. A verb which takes no complements at all (such as rain) is said to have zero valency (be avalent). Valency deals not only with the number of valents with which a verb is combined to produce a WELL-FORMED sentence nucleus, but also with the classification of sets of valents which may be combined with different verbs. For example, give and put usually have a valency of 3 (trivalent), but the valents governed by the former (subject, direct object and INDIRECT object) are different from those governed by the latter (subject, direct object, and LOCATIVE ADVERBIAL). Verbs which differ in this way are said to be associated with different valency sets. The notion is similar to that used in CASE grammar, where cases are sometimes referred to as valency roles.