A2
(으)ㄹ 때 — when
How Korean builds a “when” clause with 때, why the modifier ending changes the meaning, and how it differs from 면.
때 is the noun time. A clause in front of it says which time, exactly as in any other modifier.
어릴 때 부산에 살았어요.
Eoril ttae Busane sarasseoyo.
When I was young, I lived in Busan.
한가할 때 영화를 봐요.
Hangahal ttae yeonghwareul bwayo.
When I’m free, I watch films.
A noun in front needs 때: 학생 때, 어릴 때. The copula gives 일 때 — 방학일 때.
The ending changes the meaning
This is the part worth slowing down for. ㄹ 때 is during; 았을 때 is at the point when it had happened.
한국에 갈 때 선물을 샀어요.
Hanguge gal ttae seonmureul sasseoyo.
I bought a present on my way to Korea.
한국에 갔을 때 선물을 샀어요.
Hanguge gasseul ttae seonmureul sasseoyo.
I bought a present while I was in Korea.
갈 때 — the going was in progress, so the present was bought en route. 갔을 때 — the arrival was complete, so it was bought there. One syllable, two different trips. Japanese makes the same distinction with とき.
Against (으)면
때 states when something happens. 면 sets a condition. They overlap in English when, but 때 never carries if — see (으)면.
비가 올 때 안 갈 거예요.
비가 오면 안 갈 거예요.
The sentence is conditional — the rain may not come — so it takes 면. 올 때 would describe what you habitually do during rain.
때문에 is a different word
때 plus 문 gives because of, and it attaches to nouns: 비 때문에, because of the rain. The shared syllable is a coincidence worth not reading into.