Do-insertion / Do-support

Do-insertion, also known as do-support, is a grammatical phenomenon in English where the auxiliary verb "do" is inserted into a sentence to support the main verb, often for negation, questions, or emphatic constructions. It is not used for any lexical meaning but functions to form questions, negations, or emphasize statements.

Example:

Question: "Do you like coffee?"

Negation: "I do not like coffee."

Emphasis: "I do like coffee!"