Extraction island

In linguistics, wh-movement (also known as wh-fronting or wh-extraction or long-distance dependency) concerns special rules of syntax—rules observed in many languages around the world—involving the placement of interrogative words. The special interrogatives, whatever the language, are known within linguistics as wh-words (so named because most interrogative words in the English language start with a wh-; for example, who(m), whose, what, which, etc.). Wh-words are used to form questions, and can also occur in relative clauses. In languages exhibiting wh-movement, 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.

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.

Historically, the name wh-movement 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.

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