Regrettably: -다니(요)

At its core, -다니(요) is a way of quoting something and then reacting to it. It is actually a shortened version of -다고 하니. The 요 at the end makes it polite when finishing a sentence. You can use it in the middle of a sentence too. When it's in the middle, it acts like a bridge. It connects the shocking fact to your reaction. For example, "To think that it's already June, I'm so surprised!" When it's at the end, it's usually a retort. Someone says something, and you repeat it back with shock. "Wait, you're leaving already?!" (벌써 가다니요?). It turns a simple statement into a dynamic expression of emotion. It's like adding a giant question mark and an exclamation point at the same time. Use it when the reality in front of you doesn't match what you expected.

1. 1Learning how to build this is quite simple. It follows the standard rules for indirect citations. Here is how you do it:
2. 2For Verbs in the present tense, add -ㄴ/는다니(요). Use -ㄴ다니 if there's no patchim (final consonant). Use -는다니 if there is one. For example, 가다 (to go) becomes 간다니. 먹다 (to eat) becomes 먹는다니.
3. 3For Adjectives, just add -다니(요) to the stem. 춥다 (to be cold) becomes 춥다니. 비싸다 (to be expensive) becomes 비싸다니.
4. 4For Nouns, use -(이)라니(요). If the noun ends in a vowel, use -라니. If it ends in a consonant, use -이라니. 친구 (friend) becomes 친구라니. 선생님 (teacher) becomes 선생님이라니.
5. 5For Past Tense, use -았다니/었다니(요). 갔다니 (to think they went). 먹었다니 (to think they ate).
6. 6For Future Tense, use -겠다니(요) or -(으)ㄹ 거라니(요). 하겠다니 (to think they will do it).

This grammar is perfect for several real-world situations. Imagine you are at a fancy restaurant. You see the bill and it's 200,000 won for a salad. You'd gasp, "샐러드가 이렇게 비싸다니요!" (To think a salad is this expensive!). Use it when you receive unexpected news. If a colleague is suddenly quitting, you might say, "갑자기 그만두다니요!" (I can't believe you're suddenly quitting!). It’s also great for expressing regret about a situation. "벌써 방학이 끝났다니 슬퍼요." (To think that vacation is already over, I'm sad.). You can also use it to praise someone in a way that shows disbelief at their skill. "한국어를 그렇게 잘하다니 대단해요!" (To think you speak Korean that well, it's amazing!). It’s all about that emotional spark. If you feel nothing, don't use it. If you feel a "Whoa!", this is your go-to pattern.

Don't use this for boring, everyday facts. If you say "해는 동쪽에서 뜬다니요" (To think the sun rises in the east), people will look at you weirdly. It’s not for objective reporting. Also, avoid using it when you want to be very formal and detached. It is a very personal expression. If you are writing a scientific paper, keep -다니 out of it. Yes, even native speakers mess this up sometimes by overusing it for drama. Think of it like a grammar traffic light. Only go when there's an emotional "green light" of surprise. If you're just sharing info, stick to regular endings. Also, don't use it to ask a simple, non-rhetorical question. It’s not for gathering information. It’s for expressing an opinion about information you already have.

One big mistake is confusing -다니 with -다니까. The latter is used to emphasize something you already said. -다니 is for reacting to something new. If you say "먹는다니까!", you are shouting "I told you I'm eating!". If you say "먹는다니요?", you are saying "Wait, you're eating? (I can't believe it)". Another mistake is forgetting the -ㄴ/는다니 rule for verbs. Saying 가다니요 for a present action sounds a bit like an old poem. Use 간다니요 for modern conversation. Also, watch your intonation. If you use -다니요 at the end of a sentence, your voice should go up. It’s a reaction, not a flat statement. If you drop the pitch, you might sound sarcastic or rude.

How is this different from -다면서요? Good question! -다면서요 is used to confirm something you heard. "I heard you're moving, is that right?" It’s more about the information. -다니요 is about your reaction to that information. If someone says "I'm moving," and you say "이사간다면서요?", you are just confirming. If you say "이사간다니요?", you are expressing shock that they would leave. There's also -군(요). -군(요) is a mild realization. "Oh, I see, it's raining." -다니(요) is much stronger. "I can't believe it's raining in the middle of the desert!" Think of -군(요) as a nod, and -다니(요) as a wide-eyed stare.