This section discusses clauses in which the clause-initial position in representation (85) is filled by some constituent. This results in V2-clauses (that is, main clauses with the finite verb in second position) or embedded clauses with some constituent preceding the complementizer (which is then normally phonetically empty). We refer the reader to Section 9.1 for a more detailed discussion of representation (85).

In main clauses, the unmarked filler of the clause-initial position is the subject of the clause, as in (86a), but there are at least four marked constructions in which some other constituent precedes the finite verb: wh-questions such as (86b), topicalization constructions such as (86c), and exclamative constructions such as (86d). The use of traces in (86b-d) reflects the traditional hypothesis in generative grammar that these examples are derived by movement; traces indicate the base position of the moved phrases (here: the object position in the middle field of the clause). Alternative hypotheses are available, but will not be discussed here.

      The examples in (87) show that the clause-initial position of declarative embedded clauses normally remains empty; the complementizer precedes the subject and topicalization is excluded. Observe that the complementizer in (87b&c) is in parentheses because this element is normally not phonetically realized in Standard Dutch if the first position is filled by phonetically realized material; if the first position is (phonetically) empty, as in (87a), the phonetic content of the complementizer cannot be omitted.

The examples in (88) show that the clause-initial position is filled in embedded wh-questions, relative clauses and embedded exclamative constructions. It has been noted above that the phonetic content of the complementizer of/dat is normally omitted in written and formal Standard Dutch if the clause-initial position is phonetically filled. The complementizers are in parentheses, however, because it is often possible to overtly express the complementizer in such cases in colloquial speech as well as in certain dialects.

      In examples like (86) and (88), the result of movement is immediately visible but there are also constructions for which it has been argued that wh-movement affects a phonetically empty element, as a result of which movement can only be detected by the presence of an interpretative gap. An example of such a construction is the so-called comparative deletion construction in (89), in which we indicate the gap by means of e. Note in passing that in constructions like these one of the verbs is often omitted under identity; we indicate this here by strikethrough.

Note further that certain main clauses with V1-orders have also been analyzed as involving a phonetically element in clause-initial position; we refer the reader to Section 11.2 for a discussion of such cases.
      One of the main findings in generative grammar is that the syntactic relation between constituents in clause-initial position and their traces is subject to a set of general conditions; see Ross (1967) and Chomsky (1973/1977), and Cheng & Corver for a very brief historical review (2006). For this reason the movements found in the constructions in (86) and (88) are often referred to by means of a single cover term, wh-movement; this name is derived from the fact that in English the moved constituents often contains a word starting with wh- like the interrogative pronoun who in (90a) or the relative pronoun which in (90b).

The reader should keep in mind, however, that the notion of wh-movement covers all movements in (86) and (88), and not only those involving an interrogative or a relative pronoun. The following sections will successively discuss wh-movement in wh-questions (Section 11.3.1), in relative clauses (Section 11.3.2), in various types of topicalization constructions (Section 11.3.3), in exclamative constructions (Section 11.3.4), and in comparative deletion constructions (Section 11.3.5). Section 11.3.6 addresses the phenomenon of reconstruction, that is, the fact that wh-moved phrases behave in certain respects as if they still occupy their base position (the position of their trace); reconstruction is therefore often construed as strong evidence in favor of a movement analysis of wh-questions. Section 11.3.7 concludes this section on wh-movement with an appendix discussing so-called parasitic gaps, that is, interpretative gaps in the structure that only arise (under certain conditions) if some other gap is present that results from, e.g., wh-movement.