The +human pronoun wie'who' and -human pronoun wat'what' can be considered the interrogative counterparts of the third person personal pronouns. The examples in (328) show that the two interrogative pronouns can be used both as a subject and as an object.

If the pronoun is part of a PP, the behavior of the two pronouns diverges: whereas wie can readily occur as the complement of a preposition, wat behaves like the referential personal pronoun het'it' in that it triggers R-pronominalization. Most likely, this is related to the semantic distinction with respect to the feature ±human.

The primeless examples in (330) show that wie and wat can also function as nominal predicates in copular constructions. This is, however, not possible in the vinden construction, as is shown in the primed examples.

Note that we do find examples such as (331), but this case is rather special in that wat seems to question a property: at least, a typical answer to this question would involve an adjectival predicate and not a nominal one. Another special use of wat is illustrated in (331b), where it questions not an argument or a predicate, but a phrase, which is obligatorily present but behaves in various respects like an adjunct, for which reason it is often considered a quasi-argument of the verb; cf. Rizzi (1990).

Finally, note that the earlier mentioned restriction that wat cannot occur as the complement of a PP does not hold in echo-questions like (332a), in which the question word is stressed. In echo-questions contexts wat can also be used to as a request to repeat/clarify an earlier utterance; example (332b) shows that in this case wat sometimes alternates with the form watte.

      The examples in (333) show that the interrogative pronouns are formally third person: this is clear from the form of the finite verb and from the fact that the third person possessive pronoun zijn'his' can take the interrogative pronoun as its antecedent.

The two pronouns differ, however, with respect to number: the form of the finite verb in (334a) shows that, formally, the +human pronoun wie can be either singular or plural; the fact that the -human pronoun wat in (334b) is only compatible with the singular form of the finite verb shows that, formally, it is singular. This does not imply that it cannot be used to question more than one thing: an answer to (334b) can easily involve a list of objects. The fact that the quantifier allemaal can be used in (334b) also indicates that wat can be semantically plural; cf. Zij zijn allemaal ziek'they are all ill' versus *Hij is allemaal ziek'He is all ill'.

Example (335a) shows that using the quantifier allemaal may give rise to a marked result if the +human pronoun wie triggers singular agreement on the verb. It is, however, not hard to find fully acceptable cases like these on the internet. Singular agreement can, for instance, regularly be found with the verb komen'to come' in (335a'). Perhaps this is related to the fact that this verb may take a secondary predicative in the form of a PP, given that copular constructions like (335b&b') are also clear exceptions to the general tendency to avoid singular agreement in the presence of allemaal.

      The fact that the examples in (334) and (335), in which the pronoun functions as the subject of the clause, contain the expletive er'there' shows that the interrogative pronouns are indefinite: if the expletive is dropped, the result is unacceptable, unless some presuppositional constituent is present; cf. (328a) and (333a).

      The examples in (337) show that the pronouns wie and wat can be modified by elements like dan ook or om het even. However, this results in the loss of their interrogative force: the meaning of these phrases comes close to English formations with any. Perhaps this is not so surprising for wat, given that we will see in the Section 5.2.1.3 that this pronoun can also be used as a quantificational personal pronoun, but it is for wie, which lacks this option.

Interrogative personal pronouns do not readily allow other forms of modification. The examples in (338) involving postmodification, for example, are marginal at best.