Korean Question Formation and Interrogative Words

Asking questions is fundamental to any conversation, and in Korean, mastering interrogative patterns is the key to moving beyond simple statements into genuine dialogue. Understanding the core question words and how they interact with Korean sentence structure, verb endings, and politeness levels will transform your ability to gather information, express curiosity, and engage naturally with speakers.

The Core Interrogative Words (의문사)

Korean question words, known as 의문사, are your essential toolkit. Each one replaces a specific piece of information you are seeking. Their placement within a sentence is flexible, but they typically come before the verb.

• 누구 means "who." It is used to ask about people. In subject position, it often combines with the subject marker 가 to become 누가. For example, "Who is coming?" is 누가 와요?
• 무엇 means "what." In spoken Korean, it is almost always shortened to 뭐. You use it to ask about objects, ideas, or actions. "What is that?" becomes 저게 뭐예요?
• 어디 means "where." It inquires about location or destination. "Where are you going?" is 어디 가요?
• 언제 means "when." This word asks about time, from specific moments to general periods. "When does the movie start?" is 영화가 언제 시작해요?
• 왜 means "why." It seeks a reason or cause. "Why are you laughing?" is 왜 웃어요?
• 어떻게 means "how." It asks about the method, manner, or state of something. "How do I go to the station?" is 역에 어떻게 가요?

Forming Yes-No Questions with Intonation

The simplest way to form a question in Korean requires no question word at all. You can transform any statement into a yes-no question simply by changing your intonation. The sentence structure remains identical; only the rising pitch at the end signals that you are asking a question.

• Statement: 집에 가요. (I am going home.)
• Question: 집에 가요? (Are you going home?)

This method is incredibly common in casual and polite speech. The verb ending does not change. Pay close attention to the listener's tone to distinguish between a statement like "You are eating" (밥을 먹어요) and a question like "Are you eating?" (밥을 먹어요?). The rising intonation is subtle but crucial.

Question-Ending Verb Forms and Indirect Questions

While intonation is powerful, Korean also has specific verb endings that grammatically mark a question. Their usage is heavily influenced by formality and nuance.

• -ㄴ/은가(요) / -나(요): These endings are used in formal polite speech (합쇼체) and carry a slightly more objective or inquisitive tone. They are common in written questions or formal announcements. For descriptive verbs (adjectives), you attach -ㄴ가(요) after a vowel and -은가(요) after a consonant. For action verbs, you use -나(요). For example, "Is it far?" is 멀은가요? and "Are you leaving?" is 가나요?
• -니: This ending is used in intimate, casual speech (해체) between close friends or to those younger than you. It conveys a sense of familiarity. "Are you tired?" becomes 피곤하니? and "Did you eat?" is 밥 먹었니?

Choosing the correct ending involves understanding the pragmatic differences between question forms. Using -니 with someone you should respect can be seen as rude, while overusing formal endings with close friends can create unnecessary distance.

An indirect question is when you embed a question within a larger sentence, such as "I don't know where it is." In Korean, you form this by attaching the question word and the verb clause directly to a main verb like 알다 (to know) or 말하다 (to tell). The embedded question clause must end in a plain form verb (the dictionary form or past tense plain form), followed by 지.

• "I know where he lives." = 그가 어디 사는지 알아요. (사는 = plain form of 살다)
• "I don't know what to do." = 무엇을 해야 할지 모르겠어요.

Common Pitfalls

1. Misplacing the Question Word: While word order is flexible, placing the question word too far from the verb can confuse the listener. Keep the connection clear. Incorrect: 김치를 당신은 어디에서 먹었어요? (Scattered). Better: 어디에서 김치를 먹었어요? (Where did you eat kimchi?)

1. Confusing 무엇 (뭐) and 무슨: 무엇/뭐 stands alone as "what." 무슨 is a determiner meaning "what kind of" and must be followed by a noun. Incorrect: 무슨 해요? (Ungrammatical). Correct: 뭐 해요? (What are you doing?) Correct: 무슨 음식을 좋아해요? (What kind of food do you like?)

1. Overusing Formal Question Endings in Casual Settings: Relying only on -ㄴ가요 or -나요 can make you sound stiff or distant with friends. Practice using intonation-based questions and the casual -니 ending where appropriate.

1. Forgetting the Plain Form in Indirect Questions: Using polite forms (-아요/어요) inside the 지 clause is a common error. Incorrect: 그가 언제 올지 몰라요. (올 = polite form). Correct: 그가 언제 오는지 몰라요. (오는 = plain form).

Summary

• The six core interrogative words—누구 (who), 무엇/뭐 (what), 어디 (where), 언제 (when), 왜 (why), and 어떻게 (how)—replace specific information and are placed before the verb.
• You can form simple yes-no questions by raising your intonation at the end of a statement without changing its grammar.
• Specific verb endings like -ㄴ/은가요, -나요, and -니 mark questions grammatically, with their use dictated by formality level and the speaker's intended nuance.
• To form indirect questions (e.g., "I know where it is"), attach a clause ending in a plain form verb + 지 to a main verb like 알다 or 말하다.
• Rhetorical questions are used extensively for emphasis and expression, not to seek information.
• Always choose your question form based on the social context, as the pragmatic differences between formality levels are significant in Korean communication.