Learn Hardcore Korean: da-eum jumare chinguwa bakmulgwane gagiro haesseoyo. - I decided to go to the museum with a friend next weekend.

The suffix -기로 했어요 attaches to a verb stem (가다 → 가기로 했어요) and means “have decided (to do something)” or “have agreed (to do something).” Here, it tells us the speaker made a plan or arrangement to go: “I’ve decided (or we’ve decided) to go.”

Why are there two -에 particles in 다음 주말에 친구와 박물관에 가기로 했어요?

They mark two different things:
• 다음 주말에 – -에 is a time marker, meaning “at/around next weekend.”
• 박물관에 – -에 is a destination marker with 가다, meaning “to the museum.”

Why is 친구와 used here instead of 친구랑 or 친구하고? Are they the same?

All three mean “with a friend,” but they differ in style:
• 친구와 – more formal or written style.
• 친구하고 – neutral, common in speech.
• 친구랑 – casual, colloquial.
You can choose based on formality, but the basic meaning stays “with a friend.”

Can you explain the word order of this Korean sentence compared to English?

Korean generally follows Subject–Time–Place–Object–Verb. In our example (with the subject implied):

Time: 다음 주말에 (“next weekend”)
Accompaniment/with: 친구와 (“with a friend”)
Destination/place: 박물관에 (“to the museum”)
Verb+ending: 가기(로 했어요) (“decided to go”)
In English we might say, “Next weekend, I decided to go to the museum with a friend,” but Korean places the verb (with final endings) at the very end.

Why is there no subject like 저는 or 우리는 at the start?

Korean often omits the subject when it’s clear from context. Here, the speaker implies “I” (저는) or “we” (우리는). If you need clarity or emphasis, you can add it: 저는 다음 주말에 … 가기로 했어요.

What’s the difference between 가기(로 했어요) and 갈 거예요?

• 가기(로 했어요) – emphasizes a decision or agreement already made (“I’ve decided/it’s been arranged”).
• 갈 거예요 – simple future tense (“I will go”), expressing intention or prediction without the nuance of a prior decision/arrangement.

Could I use 에서 instead of 에 after 박물관 here?

No, when you use 가다 (to go), you mark the target of motion with -에. 박물관에서 would mean “at the museum,” indicating location of an action (e.g., 박물관에서 사진을 찍었어요 – “I took pictures at the museum”).