Learn Korean: 언제 + Verb

Let’s take a look at the Korean sentence pattern 언제 + Verb.  We use this to make when questions. It transforms depending on the verb of the question. In the case of 이다 (be verb), we attach it to 언제 as if they are one word together (언제이다). It is then conjugated into any of the following: 언제입니까 (formal),  언제예요 (polite) and 언제야 (casual). The subject (noun) of the question is placed before it. Here are some examples in casual speech: 생일이 언제야? (When is your birthday?), 파티가 언제야? (When is the party?), and 학교 첫날이 언제야? (When is the first day of school?) The subject particle (이/가) is attached to the subject, but the topic particle (은/는) is also used. In the case of other verbs, 언제 comes before them but unlike other question words, particles are  less likely used. Here are some examples: 언제 와? (When are you coming?), 언제 태어났어? (When were you born?), and 언제 결혼할 거야? (When are you getting married?) We attach 부터 to ask when an action starts and 까지 to ask when it ends. Examples are 언제부터 그런 거 입어? (Since when you started wearing those?) and 언제까지 해야 돼요? (Until when do I have to keep doing it?)

언제 처음어로 만났어?

When did you first meet?

언제 가도 돼요?

When is it okay to go?

언제부터 해요?

When do I start doing it?