eoje bame jami an wasseoyo.

I couldn’t fall asleep last night.

Breakdown of eoje bame jami an wasseoyo.

• ~이: subject particle
• 어제: yesterday
• 오다: to come
• 안: not
• ~에: time particle
• 밤: night
• 잠: sleep

Questions & Answers about eoje bame jami an wasseoyo.

Why does it say 잠이 안 오다 (sleep doesn’t come) instead of using a verb meaning to sleep?

Korean often expresses “can’t sleep” as 잠이 안 오다, literally “sleep doesn’t come.” It’s an idiomatic, very common way to say you couldn’t fall asleep.
If you use the verb 자다 (to sleep), it tends to sound like “didn’t sleep (at all)” rather than “couldn’t fall asleep,” e.g. 어제 밤에 못 잤어요.

What does 안 mean here, and where does it go?

안 is the simple negation meaning “not.” It usually goes directly before the verb/adjective, so 오다 → 안 오다 (“doesn’t come”).
Here: 잠이 안 왔어요 = “sleep didn’t come (to me).”

What’s the difference between 안 왔어요 and 못 왔어요 in this kind of sentence?

• 안 = “not” (a straightforward negation; can imply choice in some contexts)
• 못 = “can’t / unable to” (ability/circumstances)

With sleep, both occur:

• 잠이 안 왔어요: natural idiom, “I couldn’t fall asleep / sleep wouldn’t come.”
• 잠이 못 왔어요: possible, but less common; more clearly “sleep couldn’t come (due to circumstances).”
  Many speakers prefer 잠이 안 왔어요 or 잠이 안 와서….

Why is the subject marker 이 used after 잠?

In 잠이 안 오다, 잠 is treated as the grammatical subject: “sleep” is what “doesn’t come.”
So 잠이 (sleep + subject marker) is natural here. In casual speech, particles are often dropped: 어제 밤에 잠 안 왔어요.

What does -에 in 밤에 do?

-에 marks a time or place “at/in/on.”

• 어제 밤에 = “last night” (at night yesterday)

It’s very common with time expressions: 아침에 (in the morning), 3시에 (at 3 o’clock).

Is 어제 밤에 the same as 어젯밤에?

They mean the same thing (“last night”).

• 어젯밤(에) is a fixed, very common combined form.
• 어제 밤(에) is also fine and understandable, just a bit more “separated.”

Both are natural in conversation.

Why is 왔어요 (came) in the past tense used?

Because you’re talking about a completed past time period: last night.
오다 → 왔어요 is the past polite form, so the sentence means “sleep didn’t come (to me) last night.”

What’s the dictionary form of 안 왔어요?

The dictionary form is 안 오다 (“not come”).
Conjugation:

• 오다 → 와요 (present polite)
• 오다 → 왔어요 (past polite)
  So 안 왔어요 corresponds to 안 오다 in the past polite.

Is the speaker (“I”) missing? How do Koreans know who couldn’t sleep?

Yes, the subject “I” is omitted because it’s understood from context. Korean often drops obvious subjects.
If you want to specify:

• 저는 어제 밤에 잠이 안 왔어요. (As for me, I couldn’t sleep last night.)
• 어제 밤에 제가 잠이 안 왔어요. (I—specifically—couldn’t sleep last night.)

How would you say this more casually or more formally?

• Casual (to friends): 어제 밤에 잠이 안 왔어.
• Standard polite (as given): 어제 밤에 잠이 안 왔어요.
• More formal polite: 어제 밤에 잠이 안 왔습니다.

How is this different from 어제 밤에 안 잤어요?

They’re related but not identical:

• 어제 밤에 잠이 안 왔어요: “I couldn’t fall asleep / sleep wouldn’t come” (focus on difficulty falling asleep).
• 어제 밤에 안 잤어요: “I didn’t sleep last night” (can imply you stayed up and didn’t sleep at all, possibly by choice).
• 어제 밤에 못 잤어요: “I couldn’t sleep” (common and close in meaning, using 자다).

Can I replace 잠이 안 왔어요 with 잠이 안 와요?

It changes the time frame:

• 잠이 안 왔어요: past (last night, earlier)
• 잠이 안 와요: present/general (right now / these days), e.g. 요즘 잠이 안 와요 = “These days I can’t sleep.”

What are common follow-up phrases using this structure?

A few very common ones:

• 어제 밤에 잠이 안 와서 피곤해요. = “I couldn’t sleep last night, so I’m tired.”
• 걱정돼서 잠이 안 왔어요. = “I was worried, so I couldn’t sleep.”
• 커피를 마셔서 잠이 안 왔어요. = “I drank coffee, so I couldn’t sleep.”