Wh-movement

Wh-movement (or wh-fronting or wh-extraction or long-distance dependency) is a mechanism of syntax that helps express a question (or form a relative clause). Sentences or clauses containing a wh-word show a special word order that has the wh-word (or phrase containing the wh-word) appearing at the front of the sentence or clause, e.g Who do you think about?, instead of in a more canonical position further to the right, e.g. I think about you. The term wh-movement is used because most English interrogative words start with wh-, for example, who(m), whose, what, which, etc. Wh-movement often results in a discontinuity, and in this regard, it is one of (at least) four widely acknowledged discontinuity types, the other three being topicalization, scrambling, and extraposition. Wh-movement is found in many languages around the world, and of these various discontinuity types, wh-movement has been studied the most.

The actual term wh-movement itself stems from early Generative Grammar (1960s and 1970s) and was a reference to the transformational analysis of that day, whereby the wh-expression appeared in its canonical position at deep structure and then moved leftward out of that position to land in its derived position at the front of the sentence/clause at surface structure. Many modern theories of syntax do not acknowledge movement in the traditional sense, however. Despite this fact, the term wh-movement (or wh-fronting or wh-extraction) survives and is widely used to denote the underlying phenomenon even by those theories that do not acknowledge movement.