Vietnamese Question Words: ai, gì, ở đâu, and More

Once you can ask questions, conversations open up fast. The good news is that Vietnamese question words are short, there are only a handful to learn, and you can practice them free, no login. The one rule that trips people up is where they sit in the sentence, so we will cover that too.

The core five

Start here and you can ask most everyday questions.

Vietnamese	Meaning	Example
ai	who	Ai là giáo viên? (Who is the teacher?)
gì	what	Bạn ăn gì? (What do you eat?)
ở đâu	where	Bạn sống ở đâu? (Where do you live?)
khi nào	when	Khi nào bạn đi? (When do you go?)
tại sao	why	Tại sao bạn học? (Why do you study?)

Two more come up constantly: thế nào (how) and bao nhiêu (how much or how many). For counting questions, pair bao nhiêu with what you learned in numbers in Vietnamese.

The big rule: question words stay in place

In English we move the question word to the front: "What do you eat?" Vietnamese usually leaves it exactly where the answer would go:

• Bạn ăn gì? (You eat what?)
• Bạn tên là gì? (Your name is what? meaning "What is your name?")
• Bạn sống ở đâu? (You live where?)

This feels strange for about a day, then it clicks: you build a normal sentence and drop the question word into the slot you are asking about. It is the same word order you already met in Vietnamese sentence structure.

The two exceptions start the sentence, just like English:

• ai when it is the subject: Ai nấu cơm? (Who cooks?)
• tại sao (why): Tại sao bạn buồn? (Why are you sad?)

How and how much

Two more question words pull their weight every day:

• thế nào (how) goes at the end: Bạn thấy thế nào? (How do you feel?). You will also hear the longer như thế nào with the same meaning.
• bao nhiêu (how much or how many) is your money-and-counting word: Cái này bao nhiêu tiền? (How much is this?). For small countable things you can also use mấy: Bạn có mấy anh chị em? (How many siblings do you have?). When you count the nouns in the answer, you will also reach for the right classifier.

A quick note on "why": tại sao, sao, and vì sao all mean the same thing. Sao is the short, casual one you will hear most in speech.

A neat trick: position can show tense

Vietnamese has no verb tenses, so khi nào uses position to tell past from future:

• At the front, it asks about the future: Khi nào bạn đi? (When will you go?)
• At the end, it asks about the past: Bạn đi khi nào? (When did you go?)

You will also hear bao giờ and lúc nào used the same way for "when." Do not stress about mastering this on day one; just notice it so the pattern makes sense later, the way the tones and grammar feel less scary once you see the logic.

Question words vs yes or no questions

These question words ask for specific information. To ask a simple yes or no question, you do not need them at all. Just add không? at the end:

• Bạn khỏe không? (Are you well?)
• Bạn thích cà phê không? (Do you like coffee?)

So you really have two tools: không? for yes or no, and the question words above for everything else.

Common beginner mistakes

• Fronting the question word like English. It is Bạn ăn gì?, not "Gì bạn ăn?". Build the normal sentence first, then drop the question word into the slot you are asking about.
• Forgetting that ai changes position. As the subject it leads (Ai gọi bạn? = Who called you?); as the object it stays at the end (Bạn gọi ai? = Who did you call?).
• Mixing up không? and the question words. Use không? only for yes or no questions, never together with a question word.

Put it together

A few full questions you can use today:

• Bạn tên là gì? (What is your name?)
• Bạn là người nước nào? (What country are you from?)
• Nhà vệ sinh ở đâu? (Where is the toilet?)
• Cái này bao nhiêu tiền? (How much is this?)

Mix these into the lines from the basic Vietnamese phrases guide and the greetings you already know, and you can hold a real back-and-forth. For a full path from here, see the beginner roadmap.

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Sources

1. Vietnamese question formation. Linguistic reference for in-situ question words, the subject-position exception for ai, the front position of tại sao, the khi nào front/end tense distinction, and yes/no questions with không.

Frequently asked questions

What are the question words in Vietnamese?

The core five are ai (who), gì (what), ở đâu (where), khi nào (when), and tại sao (why). Two more you will use often are thế nào (how) and bao nhiêu (how much or how many).

Where do question words go in a Vietnamese sentence?

Usually in the same spot as the answer would go, not moved to the front like English. 'Bạn ăn gì?' is literally 'You eat what?' The main exceptions are 'ai' as the subject and 'tại sao', which start the sentence.

How do you say why in Vietnamese?

Use 'tại sao' at the start: 'Tại sao bạn học tiếng Việt?' (Why do you study Vietnamese?). 'Sao' and 'vì sao' mean the same thing and are common in speech.

How do you ask a yes or no question in Vietnamese?

Add 'không?' at the end: 'Bạn khỏe không?' (Are you well?). This is separate from the question words, which ask for specific information.