Korean -던데: "I Noticed That..." in Your Diary

You walked past a café and saw a long line. You met a friend who looked tired. You checked the weather yesterday and it was freezing. Then you want to say what you did about it, or how today turned out differently. Korean has an ending for exactly this moment: -던데. It says "I saw this myself earlier," and then it opens the door to the next sentence. It is a lovely ending for diary entries about things you noticed during your day.

How to form it

Attach it to the stem of a verb or an adjective. For a noun + 이다, use 이던데 (after a vowel, 이 is often dropped in speech: 의사던데).

Word type	Form	Example
Verb	stem + 던데	카페 앞에 사람들이 줄을 서 있던데 무슨 일이 있었을까? — People were lined up in front of the café. I wonder what was going on.
Adjective	stem + 던데	어제는 날씨가 춥던데 오늘은 따뜻하다. — It was cold yesterday, but it's warm today.
Noun	이던데	옆집 사람이 대학생이던데 몇 학년인지 궁금하다. — The neighbor seems to be a college student (from what I saw). I wonder what year they are in.
Past	았/었던데	어제는 길이 많이 막혔던데 오늘은 괜찮았다. — The roads were really jammed yesterday, but today was fine.

Adjectives with irregular stems keep their usual shape before a consonant: 춥다 becomes 춥던데, and 예쁘다 becomes 예쁘던데. For 하다 verbs and adjectives, it is simply 하던데: 친구가 요즘 운동을 열심히 하던데.

What it means: something you saw yourself, as a starting point

The -더- part is a "recollection" marker. It tells the listener that you personally saw, heard, or experienced the thing. The -ㄴ데 part is the familiar ending that sets a background or hints at a contrast. Put together, A-던데 B means roughly "I noticed A (back then), and/so/but B."

• 친구가 피곤해 보이던데 무슨 일 있나? — My friend looked tired. I wonder if something's wrong.
• 시험 공부를 열심히 하던데 결과가 궁금하다. — I saw them studying hard for the exam, so I wonder how it turned out.
• 새로 생긴 빵집에 사람이 많던데 내일 가 볼까? — The new bakery had lots of people, so shall I try it tomorrow?
• 그 영화 재미있던데 한번 봐 봐. — I thought that movie was fun, so give it a try.

The second clause can be a result, a contrast, a question, or a suggestion. That openness is typical of -ㄴ데 endings. The first clause is a witnessed background, and what follows is up to you. It sounds most natural when the second clause is what you think, ask, or suggest now. When the second clause is simply the action you took in reaction to what you saw, -길래 is often the smoother choice: 친구가 피곤해 보이길래 커피를 사 줬다.

The first-person rule

Because -던데 means "I observed this," it usually sounds odd when the subject is you and the action is something you did on purpose. You do not normally watch yourself doing things. It is usually natural for other people, for things, and for the situation around you.

It also works for your own feelings and impressions, which you can "observe" in yourself: 저는 그 영화가 재미있던데 (I found that movie fun). For your own deliberate actions, use a plain past form with -는데 instead: 어제 영화를 봤는데 재미있었다.

-던데 vs -는데 vs -더라

Ending	Feeling	Example
-는데	Background or contrast, no claim about how you know it	비가 오는데 우산 있어? — It's raining, do you have an umbrella?
-던데	Background or contrast you saw yourself earlier	아까 비가 오던데 우산 있어? — It was raining earlier (I saw), do you have an umbrella?
-더라	A plain report of what you saw, with nothing more attached	아까 비가 오더라. — It was raining earlier.

The easy way to remember: -는데 sets the scene, -더라 reports a sighting, and -던데 does both. You report what you saw and also keep the sentence open for what comes next.

Ending a sentence with -던데요

You can also stop right after -던데 and let the sentence trail off. Add 요 and it becomes polite: -던데요. This is very common in conversation, and it has two typical jobs.

1. A gentle disagreement. You are not saying "you're wrong." You are saying "that's not what I saw."
   • A: 그 식당 별로래요. B: 저는 맛있던데요. — A: I heard that restaurant isn't good. B: I thought it was tasty, though.
   • A: 오늘 학교 쉬어요? B: 아니요, 아까 학생들이 있던데요. — A: Is school closed today? B: No, there were students there earlier.
2. A soft remark that invites a reaction.
   • 오늘 날씨가 꽤 춥던데요. — It's pretty cold today, you know.
   • 한국어 정말 잘하시던데요! — You speak Korean really well, I noticed earlier!

The trailing -던데요 leaves something unsaid, such as "so maybe you should reconsider" or "I was impressed." The listener fills it in. In a diary, you can use the same softness to record what someone said to you or what you answered. For a person you should honor, put the honorific -시- before the ending: 선생님이 오시던데요.

Common mistakes

Mistake	Fix	Why
나는 어제 영화를 보던데 ✗	어제 영화를 봤는데 ✓	Your own deliberate action is not something you "witnessed." Use -는데 or -았/었는데.
학생던데 ✗	학생이던데 ✓	After a noun ending in a consonant, you need 이 before 던데.
친구가 가는던데 ✗	친구가 가던데 ✓	Attach 던데 to the plain stem. Do not add -는.
어제 사람이 많았더데 ✗	어제 사람이 많았던데 ✓	The ending is 던데. Watch the spelling.
선생님이 오던데요 (to show respect)	선생님이 오시던데요 ✓	Add -시- when the subject deserves honorific speech.

One more tip: if you did not see something yourself but only heard about it, -던데 is usually the wrong tool. Reported news takes a different shape, such as 온다던데 ("I heard it's coming").

Try it in tonight's entry

Think of something you noticed today, and use it as the opening of a longer sentence:

• 퇴근길에 길이 막히던데 지하철을 탈 걸 그랬다.
• 동료가 오늘 기분이 좋아 보이던데 무슨 일이 있었나 보다.
• 회사 근처에 새 카페가 생겼던데 내일 가 봐야겠다.
• 창밖을 보니 눈이 오던데 내일은 일찍 일어나야겠다.

Notice how each line starts with something you actually saw, then moves on to your thought or action. That small habit turns a list of events into a story. Want to check that your -던데 sentences sound natural? Write your diary at kdiaryai.com and get instant corrections.