The words that form questions in English
Interrogative pronouns introduce direct or indirect questions by replacing unknown information. The five primary interrogative pronouns are who, whom, whose, which, and what, with whoever, whomever, whichever, and whatever as emphatic forms.
In informal US English, "who" often replaces "whom" ("Who did you give it to?" vs. UK "To whom did you give it?").
Required after prepositions in formal writing ("For whom is this intended?"). Increasingly replaced by "who" in spoken English.
❌ "Who's" (contraction) vs. ✅ "Whose" (possessive). Oxford cautions: "'Who's' is never a possessive form."
Used when the possible answers are restricted or known. Contrast with "what" for open questions.
In some UK dialects, "what" replaces "who" as subject ("What stole my apples?" – West Country dialect). Non-standard.
Word order changes from question to statement form in indirect questions ("What is it?" → "I asked what it was").
US English often uses "what" + noun for open questions ("What color is it?"), while UK may prefer "which" for defined options ("Which colour [red/blue]?").
"Whoever" and "whomever" follow the same case rules as "who/whom" ("Give it to whoever asks" – subject of clause vs. "Whomever you choose" – object).