Vocabulary · 10 min read

Stop Translating Everything as "What": Korean Question Words Decoded

Most textbooks list 무슨, 무엇, 어떤, 어느, 얼마, and 몇 all as "what" or "which." That translation is not wrong, but it hides the real distinctions. Each word occupies a specific grammatical role, and mixing them up produces errors that native speakers notice immediately.

You want to ask a friend "What is that?" You write 무슨이에요? Your Korean friend looks confused. Then you try "What do you do for work?" You write 뭐 일 해요? and they correct you again.

Both errors come from treating all these question words as interchangeable. They are not. Each word has a fixed grammatical function. Once you understand the function, the right word becomes obvious.

The Six Words at a Glance

뭐 / 무엇: "What" as a Pronoun

뭐 (spoken) and 무엇 (written/formal) are interrogative pronouns. They replace a noun in the sentence, filling the subject or object slot on their own. Korean grammar classifies them as 의문대명사 (interrogative pronouns).

뭐 occupies the same slot a regular noun would. "이게 뭐예요?" has the same structure as "이게 책이에요?" The question word is the noun. This is why 뭐 can take particles (을/를, 이/가), but 무슨 cannot.

무슨, 어떤, 어느: Three Modifiers, Three Roles

This is the area where most learners get tangled. All three are interrogative modifiers (Korean grammar calls them 의문관형사): they must precede a noun and cannot stand alone. But they ask fundamentally different questions.

무슨: Open, category-level inquiry

무슨 is used when the speaker has no prior knowledge of the options and is asking about the type or category of something in a completely open-ended way. The question imposes no expectations on the answer.

어떤: Quality-level inquiry

어떤 asks about specific qualities, characteristics, or attributes of something, often when the speaker already has some familiarity with the options or wants a descriptive answer rather than a category name.

어느: Selection from a defined set

어느 implies that a specific set of options exists and the speaker is asking for one to be identified from that set. Countries, floors, directions, people in a room, items on a menu: anything with a finite, defined group calls for 어느.

The Modifier Rule: 무슨 Cannot Stand Alone

The single most common error is using 무슨 where 뭐 is needed, or vice versa. The test is simple: if the question word is directly followed by a noun (no particle between them), it must be 무슨, 어떤, or 어느. If it needs to stand alone or follow a particle, it must be 뭐.

얼마 vs 몇: Two Very Different "How Much"s

Both words relate to quantity but they ask completely different questions, and the number system used in the answer is different too.

몇 always precedes a counter word. It cannot be used without one, and it cannot ask about price.

* Floor numbers (층) use Sino-Korean, which is an exception to the general Pure Korean counter rule.

얼마나: asking about degree or duration

얼마나 extends 얼마 into an adverb meaning "how much / to what extent / how long." Unlike 몇, the answer can be vague or descriptive.

Why the Textbook Translation Fails

English "what" covers multiple grammatical roles depending on context, and Korean separates those roles into distinct words. When textbooks collapse all of them into "what" and "which," learners have no grammar rule to apply. They guess, and they guess wrong in patterned ways.

The underlying grammar categories are clean once you see them:

• Pronouns (의문대명사): 뭐/무엇, 얼마 replace a noun directly and can stand alone or take particles.
• Modifiers (의문관형사): 무슨, 어떤, 어느, 몇 must directly precede a noun and cannot stand alone.

Within the modifiers, the distinction is about the speaker's relationship to the options: no knowledge (무슨), qualities in mind (어떤), known set (어느), specific count (몇).