Learn Hardcore Korean: hwayoireneun hangugeo sueobi isseoyo.

화요일에 simply marks time—“on Tuesday.”
화요일에는 combines 에 (time marker) + 는 (topic particle), so it means “as for Tuesdays.” Adding 는 adds emphasis or contrast (e.g. “On Tuesdays (but not on other days)…”).

What does 한국어 literally mean and why is the suffix 어 used?

한국 means “Korea,” and 어 means “language.” So 한국어 is “the Korean language.” Korean uses the same pattern for other languages: 영어 (English), 스페인어 (Spanish), 중국어 (Chinese), etc.

What does 수업 mean in this context?

수업 means “class” or “lesson” (a scheduled teaching session). It’s the general word for attending or giving instruction.

Why do we use the subject marker 이 in 수업이 instead of the object marker 을?

The verb 있다 (“to have” or “to exist”) is treated as a descriptive/existential verb. Nouns linked to descriptive verbs take the subject marker (이/가), not the object marker (을/를).

Why is the verb 있어요 at the end, and what form is it?

Korean follows Subject-Object-Verb (SOV) word order, so the verb always comes last. 있어요 is the polite informal present-tense form of 있다 (“to exist” or “to have”), used in everyday polite speech.

How can I make this sentence negative?

Replace 있어요 with its negative 없어요:
“화요일에는 한국어 수업이 없어요.”
= “On Tuesdays, I don’t have a Korean class.”

How would I say this more formally and more casually?

• Formal polite: 화요일에는 한국어 수업이 있습니다.
• Casual (friends/family): 화요일에는 한국어 수업이 있어.

What’s the difference between 화요일에는 and 화요일마다?

화요일마다 means “every Tuesday,” emphasizing a habitual action.
화요일에는 marks Tuesday as the topic (“as for Tuesdays…”) and may imply a habit but also contrast with other days.

Why isn’t there a plural marker on 수업 if I mean multiple classes?

Korean often omits plural markers; context tells you if it’s singular or plural. If you really need to mark plural, you can add 들 (e.g. 수업들), but it’s usually unnecessary here.