Vietnamese ai asks for a person: “who” or, in a possessive phrase, “whose.” Its position is usually the same position that the unknown person would occupy in the answer. That one principle explains Ai gọi? “Who called?”, Em gọi ai? “Whom did you call?”, and Cái này của ai? “Whose is this?” without inversion or an equivalent of English do.
This page focuses on interrogative ai. Gì “what” is treated separately on Gì for What.
Put ai where the person's name would go
Start with a possible answer and replace the unknown person phrase with ai. If chị Lan is the subject in Chị Lan gọi cho em, ai remains in subject position. If chị Lan is the object in Em đang đợi chị Lan, ai remains after the verb.
Ai vừa gọi cho em thế?
Who just called you? (informal, curious)
Em đang đợi ai ở dưới sảnh?
Who are you waiting for in the lobby?
Chị gửi bản hợp đồng này cho ai?
Who are you sending this contract to?
English moves who toward the front in the second and third examples and inserts an auxiliary: “Who are you waiting for?” Vietnamese does neither. Ai occupies the object after đợi, or the recipient after cho. Vietnamese also has no formal everyday contrast like English who/whom: ai covers both.
Subject, object, companion, and owner
The grammatical role comes from position and surrounding words, not from a change in ai.
| Role sought | Vietnamese frame | Likely answer |
|---|---|---|
| subject | Ai phụ trách ca tối? | Chị Hương phụ trách. |
| direct object | Anh mời ai? | Anh mời Tuấn. |
| companion | Em đi với ai? | Em đi với bạn cùng lớp. |
| recipient | Chị gửi thư cho ai? | Chị gửi cho cô giáo. |
| owner | Đây là ô của ai? | Ô của chú Minh. |
Ai phụ trách phòng này ạ?
Who is in charge of this room? (deferential)
Cuối tuần này con đi cắm trại với ai?
Who are you going camping with this weekend?
Chiếc áo mưa để cạnh cửa là của ai vậy?
Whose raincoat is the one by the door? (informal)
Của ai is the normal way to ask about ownership. In a compact noun phrase, áo ai can mean “whose shirt,” but của ai is clearer and more widely useful to learners. The deferential final ạ in Ai phụ trách phòng này ạ? respects the listener; it does not turn the content question into a yes-no question.
Content questions versus polar and confirmation questions
The following minimal contrast shows how question shape encodes the required answer and the speaker's stance.
| Form | What it requests | Speaker stance |
|---|---|---|
| Bạn khỏe không? | positive or negative answer | fairly neutral polar question |
| Anh có đi không? | whether he will go | explicit positive/negative frame |
| Ai đến? | the identity of a person | open content question |
| Đi đâu? | a destination | content question; destination omitted |
| Phải không? | confirmation | speaker leans toward the proposition |
| Được chứ? | acceptance or permission | speaker expects or seeks agreement |
An ordinary ai question does not take final không. Ai sẽ thuyết trình? asks for a person; adding không would not reproduce English “Who will present?” Particle choice instead changes the act being performed.
If the speaker wants a choice between named people rather than an unrestricted identity, hay states the alternatives and ai is no longer needed.
Tối nay anh Phúc hay chị Hà sẽ trực?
Will Phúc or Hà be on duty tonight?
Unlike Tối nay ai sẽ trực?, this question presents two candidate answers. A listener can still correct its premise, but the preferred response is one of the named alternatives.
Chị Ngọc sẽ trình bày phần này, phải không?
Ms. Ngọc will present this part, right?
Chị Ngọc sẽ trình bày phần này à?
Oh, Ms. Ngọc is going to present this part? (informal reaction or confirmation)
The first speaker already has chị Ngọc in mind and requests confirmation with phải không. The second reacts to newly noticed information with à. Ai sẽ trình bày phần này? does not propose any identity at all. This is why particles cannot simply be appended as interchangeable “question markers.” See Phải Không confirmation and sentence-final À, Ư, Hả, and Sao for their broader interactional uses.
Presupposition and social calibration
Ai làm vỡ cốc? normally assumes that some person broke the cup. That assumption may sound accusatory if nobody has accepted responsibility. A polar question can be less presumptive: Có ai làm vỡ cốc không? “Did anyone break a cup?” Here ai is licensed inside a có...không frame and means “anyone,” not the open interrogative “who.”
Ai để hồ sơ này trên bàn tôi?
Who left this file on my desk?
Có ai cần tôi giải thích lại không?
Does anyone need me to explain it again?
Vietnamese pronouns also encode relationships. Bạn hỏi ai? is suitable among peers. To a younger relative, an older speaker might ask Con đang nhắn tin cho ai đấy? To a customer or senior, avoid mechanically using bạn; choose an appropriate kinship or role term and, when suitable, ạ.
Thưa cô, em cần nộp đơn này cho ai ạ?
Excuse me, who should I submit this form to, ma'am? (formal/deferential)
The frame is grammatically identical to a casual question, but thưa cô, em–cô, and ạ calibrate respect. Hả? can request repetition or convey surprise in informal speech, but it may sound abrupt toward a senior: Em đi với ai hả? is natural from an older person to a younger one, not a universal politeness model.
Answers and negative questions
Answer an ai question with the relevant person phrase, often followed by enough of the predicate to remove doubt.
— Ai đón bé Linh chiều nay? — Ông ngoại đón cháu lúc năm giờ.
— Who is picking up little Linh this afternoon? — Her maternal grandfather is picking her up at five.
Negative questions need especially explicit answers. A bare English-style yes can be interpreted from different logical viewpoints. Vietnamese normally makes the polarity and person clear.
— Không ai báo cho chị à? — Có, anh Dũng đã gọi cho chị lúc sáng.
— Didn't anyone tell you? — Yes, Mr. Dũng called me this morning.
— Chưa ai nhận việc này hả? — Chưa, mọi người vẫn đang bàn.
— Has nobody taken this task yet? — Not yet; everyone is still discussing it. (informal)
In the first reply, có rejects the negative proposition and the full clause identifies the caller. In the second, chưa confirms that the expected event remains incomplete. Do not leave the listener to infer whether “yes” agrees with the wording or with the underlying event.
A natural dialogue
— Tối nay ai trực quầy giúp chị? — Em trực đến tám giờ, rồi anh Phúc thay em.
— Who is covering the counter for me tonight? — I am until eight, then Phúc will take over for me.
— Em đổi ca với ai rồi? — Với chị Hà ạ. Chị ấy đã đồng ý.
— Who did you swap shifts with? — With Ms. Hà. She has agreed. (deferential reply)
— Vậy ngày mai chị Hà đến sớm, phải không? — Vâng, chị ấy đến lúc bảy giờ.
— So Ms. Hà is coming early tomorrow, right? — Yes, she is coming at seven.
The first question leaves the worker's identity open, the second asks for the participant after với, and the third switches to confirmation because the name is now known. The change from ai to phải không therefore changes what information is missing, not merely the tone.
Common Mistakes
1. Fronting object ai like English who.
❌ Ai em đang chờ?
Incorrect as the neutral question — English-style fronting removes ai from the object position.
✅ Em đang chờ ai ở cổng trường?
Who are you waiting for at the school gate?
2. Inventing Vietnamese do-support.
❌ Ai làm bạn đã mời đến tiệc?
Incorrect — làm cannot serve as the auxiliary do in ‘who did you invite.’
✅ Bạn đã mời ai đến dự tiệc?
Who did you invite to the party?
3. Adding final không to an open ai question.
❌ Ai sẽ đón con không?
Incorrect for ‘Who will pick you up?’ — final không asks for polarity, while ai asks for identity.
✅ Ai sẽ đón con sau giờ học?
Who will pick you up after school?
4. Giving an ambiguous one-word reply to a negative question.
⚠ — Không ai gọi cho em à? — Có.
Grammatical, but too easy for an English-speaking learner to interpret backward.
✅ — Không ai gọi cho em à? — Có, mẹ vừa gọi cho em.
— Didn't anyone call you? — Yes, Mom just called me.
Key Takeaways
- Ai means “who/whom”; của ai asks “whose.”
- Replace the unknown person in place: Ai gọi?, Em gọi ai?, Em đi với ai?
- Do not add English-style inversion, do, or final không to an open ai question.
- Use phải không? for confirmation and có...không? when the real question is whether anyone is involved.
- In negative questions, answer with an explicit person and predicate rather than an unanchored yes or no.
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