Learn Hardcore Korean: oneul iljjik toegeunhaeyo.

Temporal nouns like 오늘 (“today”), 내일 (“tomorrow”), 어제 (“yesterday”) can act as adverbs without a particle. Saying 오늘 일찍… naturally means “today early….” If you add a topic marker (오늘은), it emphasizes “As for today…” rather than simply stating when. And using 에 (e.g. 오늘에) is unidiomatic in Korean for “today.”

Why is 일찍 placed before 퇴근해요?

일찍 is an adverb meaning “early,” and in Korean, adverbs generally precede the verb they modify. So 일찍 퇴근해요 literally “early leave-work” corresponds to “leave work early.”

What exactly is 퇴근해요? How is it formed?

퇴근해요 is the polite present tense of the verb 퇴근하다 (“to leave work”). It’s made by combining the Sino-Korean noun 퇴근 (退勤, “leaving work”) with 하다 (“to do”), then conjugating 하다 into the polite 해요 form.

Why is there no subject like 저는 or 제가 in the sentence?

Korean often drops subjects when they’re understood from context. Here, it’s clear you’re talking about yourself, so 오늘 일찍 퇴근해요 is sufficient. Adding 저는 (as for me) is possible (저는 오늘 일찍 퇴근해요) but not required.

What level of politeness is ?