Section 1.1.2 has shown that the noun phrase can be divided into two subdomains, the NP- and the DP-domain: the NP-domain is headed by the noun and determines the denotation of the noun phrase, whereas the DP-domain is headed by a determiner or a quantifier/numeral and determines the referential and/or quantificational properties of the noun phrase. Thus, the internal structure of the noun phrase as a whole can be represented as in (1), in which Determiner (D) and Noun (N) are the heads of the projections DP and NP, respectively, and where the dots indicate the possible positions of other elements. In this chapter, as well as in Chapter 3, we will concentrate on the projection of the noun, that is, the NP-domain.

Each NP contains an obligatory head N and, optionally, one or more other elements, which can be further categorized according to their function, i.e., according to whether they function as complements or as restrictive modifiers. Complements are elements whose presence is required by the semantics of the head noun; the idea is that these complements are obligatory arguments of the nominal head, comparable to the complements of verbs. Restrictive modifiers, on the other hand, are not required by the semantics of the head.
      Complements are generally closer to the nominal head than the restrictive (as well as the non-restrictive) modifiers. Example (2a) illustrates this for the nominal complement tomaten'tomatoes' and the adjectival modifier gebruikelijk'usual' in prenominal position, example (2b) for the PP-complement van Jan'of Jan' and the PP-modifier in het ziekenhuis'in hospital' in postnominal position, and example (2c) for the clausal complement dat Jan ziek geworden was and the restrictive relative clause dat net binnenkwam in postnominal position.

These word order facts lead to the generalization in (3), according to which complements and modifiers are inserted at different levels within NP: complements are immediate sisters of the head noun, whereas modifiers are adjuncts inserted at some higher level in the NP. According to this assumption, the structures of the noun phrases in (2) are as indicated in (4).

The difference between complements and restrictive modifiers is often hard to determine, as the two may be categorially identical. This is not so much the case in prenominal position, where the modifier typically takes the form of an AP and the complement takes the form of a noun phrase or a PP, as in (5a), but this problem does occur in postnominal position, where complements and modifiers both may take the form of a PP or a clause, as in (5b&c).

Although the present chapter will be mainly concerned with complements, it is necessary to first address more extensively the difference between complements and modifiers: Section 2.2.1 will discuss the difference between prepositional complements and modifiers in (5b), and Section 2.3.3 the difference between clausal complements and modifiers in (5c). Modification within the NP will, however, be the main topic of Chapter 3.

The term complementation is usually associated with the verbal domain. Verbs have argument structures, specifying the number and thematic roles of their arguments. Arguments of verb must be divided into (i) internal arguments or complements and (ii) externalarguments. The former in a sense complete the predicate, as a result of which it can be predicated of the latter. In the lexical frames in (6), the external argument is underlined in order to distinguish it from the complements. The semantic arguments of the verb are normally realized as syntactic arguments: internal arguments generally surface as the objects of the verb, whereas the external argument normally corresponds to the subject.

Nouns may function as predicates as well, and are therefore also able to take arguments. This is shown in (7), in which the nominal noun phrase genie'genius' is predicated of the noun phrase Jan, which therefore functions as the external argument. Since the usual labels for semantic roles are especially created for expressing the roles of the arguments in the event structure denoted by verbal predications, we will simply refer to the external argument of nouns as the referent (Ref), that is, the entity to which the property denoted by the nominal (or adjectival) predicate applies.

The syntactic mapping of the external arguments of nouns is more complicated than that of verbs. If the noun is used as the head of a nominal predicate in a copular or vinden-construction, the mapping is rather straightforward: in (7), for example, the external argument corresponds to the noun phrase Jan, which functions respectively as the subject and the object of the clause. However, if the noun is used as the head of a noun phrase in argument position, it typically tends to be syntactically avalent: rather than behaving like a predicate with one or more arguments, the noun phrase it is part of acts as an argument of some other predicate. Correspondingly, such noun phrases do not denote a property, but typically have a referential function: they identify the entity or set of entities about which something is predicated. In (8), for instance, the noun phrase de man has the same function as Jan in (7), that is, it acts as the external argument of the nominal predicate.

This does not mean, however, that nouns heading a noun phrase in argument position do not have a predicative function: such nouns can be said to predicate something of their referential argument, that is, of the entity or set of entities referred to by means of the noun phrase. The noun phrase een man in (9a), for example, can be paraphrased as ∃x man (x): there is an entity x such that the predicate man applies to x. Correspondingly, (9a) is normally assigned the semantic interpretation in (9b), which involves the conjunction of two predicates: there is an entity x such that the predicates man and walking in the street both apply to x.

The discussion above, which is based on Williams (1981), shows that nouns always have an external argument, but that this argument is not syntactically expressed if the noun is the head of a noun phrase functioning as the syntactic argument of some other predicate, as in (9). The external argument of the noun can (and must) be syntactically realized only if the noun is heading a noun phrase that syntactically functions as a predicate, as in (7). This is given as generalization II in (10).

Complementation is not a typical property of non-derived nouns. There are, however, at least two classes of basic nouns that normally require the presence of an argument. The first is the class of relational nouns, which includes kinship nouns like vader'father', broer'brother', nicht'niece', and nouns denoting physical properties of objects like vorm'shape', gewicht'weight' or kleur'color'; see Section 1.2.3 for more examples. These relational nouns can successfully fulfill their referential function only if related to some other entity. This is illustrated in (11a) for the noun vader: this example is only acceptable if a noun phrase is present carrying the “child” role assigned by the noun vader. Another example is given in (11b): the noun vorm'shape' cannot refer independently but requires the syntactic realization of the noun phrase referring to a physical object that has some shape. Note that in accordance with generalization II in (10), the “Ref” role only needs to be expressed syntactically if the noun phrase headed by vader functions syntactically as a predicate. Complementation of the relational nouns will be discussed more extensively in Section 2.2.2.