Does this sentence sound natural? how can it be further improved?

Question

남동생을하고 같이 공원에서 운동했어요.

I mean to say that my younger brother and I went to a park and exercised together.

Thanks sm!

Answer 1

There is no need of using 을 before 하고 in this sentence.

하고 is a postpositional particle, which is attached to a noun or noun phrase. It indicates a behavior is done with someone as a partner.

을 is also a postpositional particle which indicates the noun is used as the objective case of the sentence.

You can only use one postpositional particle after a noun. So in this case, 남동생하고 같이 공원에서 운동했어요 would sound natural.