How does the grammar of 갔다 와 work?
How does the grammar of 갔다 와 work?
Does it come from the form of "갔다가"? Like 갔다가 와
Or is it a separate grammatical principle?
Also what's the difference between saying "갔다 와" and "가고 와" and "가서 와"?

Question

Answer

-다 in "갔다 오다" is a short form of -다가
-다가 : 어떤 동작이나 상태 따위가 중단되고 다른 동작이나 상태로 바뀜을 나타내는 연결 어미.

a. V. + 다가
=> "while doing," "as (something) is going on"

b. V. + 었/았다가
=> "while/when," "and then"

These connectives indicate an interrupted action followed by another action. The actor of both actions is usually the same. There are some exceptions―for example, 비가 오다가 해가 났다 "It was raining, and then the sun came out."

(a)
길을 가다가 친구를 만났어요. 
=> On my way, I met a friend.
이 길로 똑바로 가다가 왼쪽으로 가세요. 
=> Go straight this way, and then go left.

(b)
껐다가 다시 켜보면 어떨까요? 
=> How about turning it off and then turning it on?
옷을 입었다가 다른 옷으로 갈아 입었어요. 
=> I wore one set of clothes and then changed into another set.

갔다 오다 = 갔다가 오다
went somewhere and then come.

가다 오다 = 가다가 오다
while go somewhere, come back.

가고 오다(X) It is impossible for someone to go and come at the same time.
나는 가고 그는 오다(O)

가서 오다, 가 오다(X)
가서 사 오다(O)
가서 먹고 오다(O)

Answer

Yes, it's actually "갔다가 와", and literally means "to go (to do something) and then return"

Both "가고 와" and "가서 와 don't make sense.

가서 와 technically also means "to go and then return", but it doesn't allow an interval between both actions unlike "갔다 와"
e.g. 집에 가서 자: go home and sleep.

As for "가고 와", it absolute doesn't make sense.

Answer

Jeg skulle akkurat til å spørre om det samme, haha