Learn Hardcore Korean: jeoneun hakgyo kkeutnago chingudeulgwa norayo.

Yes. Korean often omits the topic when it’s clear from context. Even without 저는, it’s understood that “I” am hanging out with friends. Including 저는 adds clarity or emphasis but isn’t strictly required.

What does 학교 끝나고 mean, and how is it formed?

학교 끝나고 literally breaks down as:
• 학교 (school)
• 끝나다 (to finish) → stem 끝나
• connective ending -고 (“and/then”)
Together, it functions as an adverbial phrase meaning “after school.”

Why is there no particle like -에서 after 학교?

Here, 학교 is part of the time expression 학교 끝나고 (“after school”), not indicating location. Since it’s “the thing that finishes,” no location particle is used.

Could you also say 학교가 끝나고 친구들과 놀아요?

Yes. Adding -가 marks 학교 explicitly as the subject of 끝나다. Both 학교 끝나고 and 학교가 끝나고 are correct; the version without -가 is simply more colloquial.

What’s the difference between 끝나고 and 끝나서? Can both be used here?

Both -고 and -서 connect verbs, but:
• 끝나고 lists actions in sequence: “after it ends, I…”
• 끝나서 can imply cause/result or sequence: “since/after it ends, I…”
In this context, 학교가 끝나서 친구들과 놀아요 is also grammatically fine, but -고 is more neutral for describing events in order.

What does 친구들과 mean, and why -과?

친구들 means “friends” (들 is the plural marker). When a noun ends in a consonant (친구 ends in ㄱ), you attach -과 to mean “with.” So 친구들과 = “with friends.”

Is 친구들이랑 the same as 친구들과?

Yes. -이랑/랑 is a colloquial “with” particle (you add 이 after a consonant). 친구들이랑 and 친구들과 both mean “with friends,” but -들이랑 is more casual.

What does 놀아요 mean here?

놀아요 is the polite present-tense form of 놀다 (to play, hang out, have fun). It literally means “(I) play/hang out.” The -아요/어요 ending makes it polite speech.

Could you use an informal form instead of 놀아요?

Yes. In casual (banmal) speech you can drop -요 and say 놀아 (the informal present tense of 놀다). The dictionary form is 놀다, and 놀아 is used with close friends or younger people, whereas 놀아요 remains polite.