Government and Binding Theory/Head Movements

In interrogatives, if we move wh-elements to the beginning of the sentence, we need to move the auxiliary verb or be after it as well. Yes-no questions have a similar requirement. If there is no auxiliary verb, then English uses the do-insertion process to inject one:

(1a) You will go where? ⇒ Where will you go? (1b) You do want what from me? ⇒ What do you want from me? (1c) You are crazy? ⇒ Are you crazy?

The subject-verb inversion involved is called head movement as only the head is moved to the beginning: the rest of the phrase is untouched. It is contrasted with phrase movement, which describes the movements we've seen prior to this chapter.

The movement of the head of a phrase, rather than entire phrase.

I and V movements
The movement of English inflectional suffixes is a kind of head movement:

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As is the movement of French verbs:

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Subject-auxiliary inversion
Subject-auxiliary inversion in English moves the auxiliary in C position:

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do-insertion
In English, only auxiliaries can be moved through head movement. Lexical verbs cannot:

(2a) *Know you how to play football?

Note that other languages, such as French, allow lexical verbs to be moved to the front, and lack do-insertion. Consider this example:

(2b) Savez-vous jouer au football ? (Know you to play to the football?)

We can explain this easily as the French verb can be moved out of the VP while the English verb cannot:

⇒ ⇒

V2
In our discussion of the head parameter, we have discussed how word orders other than SVO can be derived. In our discussion of the articulated CP hypothesis, we covered more fluid word orders like Italian as well. However, we are yet to touch on V2 (Verb Second) word order, which is found in the Germanic Languages:
 * The verb is always the second element in the sentence.
 * The element to be emphasised comes first, and it can be a subject, an object or even an adjunct.