piedpiping

Pied-piping is a syntactic phenomenon in which a wh-word or other fronted constituent moves to the front of a clause together with a preposition that governs its complement. The effect is that the preposition and its object are fronted as a unit, rather than the preposition being left behind or stranded at the base position.

In English, pied-piping is often contrasted with preposition stranding. For example: "To whom did you address the letter?" and "With whom did you go to the party?" show pied-piping; by contrast, "Who did you talk to?" demonstrates preposition stranding.

Pied-piping also occurs in relative clauses: "The author to whom I spoke is famous" vs "The author I spoke to is famous." The latter uses preposition stranding. The phenomenon is not limited to questions; it also appears in various extraction contexts where a preposition governs the wh-phrase’s complement.

Pied-piping behavior varies across languages and syntactic theories. Some languages require pied-piping in questions and relatives; English allows both forms in many contexts, with stranding more common in casual speech and some dialects. In formal style, pied-piping is often preferred. The term originated in generative syntax to describe this movement pattern and is often discussed in relation to preposition stranding and wh-extraction phenomena.