Learn Hardcore Korean: jeoneun naeil sueobe chulseokhal geoyeyo.

저는 sets up “me” as the topic, giving background and sounding neutral. It can also imply mild contrast (as for me…).
제가 is the subject marker and highlights “I” as the doer, often used when answering “who?” or emphasizing that it’s specifically you.
Both are grammatically fine, but the nuance differs:
- 저는 내일 수업에 출석할 거예요. = As for me, I’ll attend class tomorrow.
- 제가 내일 수업에 출석할 거예요. = I (as opposed to someone else) will attend class tomorrow.

Can I omit 저는?

Yes. Korean often drops the subject when it’s obvious from context. 내일 수업에 출석할 거예요. is perfectly natural if listeners know you’re talking about yourself.

Why is it 수업에 and not 수업에서 or 수업을?

에 marks the target or venue you “show up to.” The verb 출석하다 (“to attend/be present”) conventionally takes -에.
에서 marks the place where an action happens (e.g., 수업에서 발표하다 “to present in class”). It doesn’t pair with 출석하다.
을/를 makes “class” a direct object, which doesn’t match the selection of 출석하다.

Is 수업에 참석하다 or 수업에 참여하다 also correct?

참석하다 is used for meetings/events/ceremonies (회의/행사에 참석하다). With classes, it’s less common; Koreans usually say 수업에 출석하다 or simply 수업을 듣다.
참여하다 emphasizes active involvement/engagement rather than mere presence. 수업에 참여하다 is fine if you mean “take part in the class activities,” not “be on the attendance sheet.”

Is 출석하다 too formal for everyday speech? What’s more natural?

In casual conversation, people more often say:

수업 가요. / 수업에 가요. (I’m going to class.)
수업(을) 들어요. (I’m taking/attending the class.) Use 출석하다 when talking about official attendance (e.g., records, policies) or in formal contexts.

How does the future form -(으)ㄹ 거예요 work here?

It expresses plan/intention or a likely future: “will/going to.”
Form: verb stem + -(으)ㄹ 거예요.
- 하다 → 할 거예요 (drop 다, add ㄹ 거예요) So 출석하다 → 출석할 거예요 = “will attend.”

What’s the difference between -ㄹ 거예요, -겠어요, -ㄹ게요, and -려고 해요?

-ㄹ 거예요: neutral plan/intention or prediction. Most common.
-겠어요: speaker’s strong will (“I’ll do it!”) or guess (“I suppose…”). Slightly formal/literary feel in the will-sense.
-ㄹ게요: a promise/commitment reacting to the listener’s situation (“I’ll do it (for you/then)”).
-려고 해요: “I’m planning/trying to,” intention in progress rather than a firm prediction.

Why is it spelled 거예요, not 거에요? And do I write 할거예요 or 할 거예요?

거예요 comes from 것이에요 → 거예요. Because 것 + 이 contracts to 거 + 예, the correct form is 거예요, not 거에요.
Spacing: write the verb and 거예요 separately: 할 거예요 (not 할거예요).
Casual equivalents: 거야 (from 것이야) and 할 거야.

How do you pronounce the sentence naturally?

A smooth, natural reading (not strict IPA) is roughly:

저는 [저는]
내일 [내일]
수업에 [수어베] (the ㅂ links to the following vowel)
출석할 [출서칼] (ㄱ + ㅎ → ㅋ)
거예요 [거예요] (often sounds like [꺼예요] colloquially) Altogether: [저는 내일 수어베 출서칼 거예요] (you’ll often hear [할 꺼예요]-type tensification in casual speech).

Why no particle after 내일? Can I say 내일에?

Time words like 어제/오늘/내일 don’t take -에 when marking when something happens. So say 내일 가요, not 내일에 가요. You can use 내일에 in other roles (e.g., 내일에 대한 계획 “plans about tomorrow”).

Can I change the word order?

Yes. Common, natural options include:

저는 내일 수업에 출석할 거예요. (subject–time–place–verb)
내일 저는 수업에 출석할 거예요. (time fronted) You could also say 수업에 내일 출석할 거예요, but time-before-place usually feels smoother unless you’re emphasizing the place.

What politeness level is this? How do I make it more formal or more casual?

Current: polite informal (-요) → 출석할 거예요.
More formal (announcements/writing): 출석할 것입니다 or 출석하겠습니다 (the latter sounds like a firm commitment).
More casual (to friends): 난 내일 수업에 출석할 거야.

How do I say “I won’t/can’t attend”?

Won’t: 출석하지 않을 거예요 / 출석 안 할 거예요.
Can’t: 출석 못 해요, or more everyday: 수업에 못 가요 / 수업(을) 못 들어요.
“I’ll be absent”: 결석할 거예요 (clear but a bit formal; often used when reporting to a teacher).

How do I ask, “Will you attend class tomorrow?”

Polite: 내일 수업에 출석할 거예요?
To a friend: 내일 수업에 출석할 거야?
To a teacher (honorific subject): 내일 수업에 출석하실 거예요? More casual, everyday alternatives: 내일 수업 갈 거예요? / 수업 들을 거예요?

Can I use 전 instead of 저는?

전 is a common contraction of 저는 in casual writing/texting and relaxed speech. It’s fine informally, but avoid it in formal writing. The rest of the sentence stays the same.

What’s the antonym of 출석하다?

결석하다 = to be absent. For example, 저는 내일 수업에 결석할 거예요 (I’ll be absent from class tomorrow). In conversation, many people simply say 내일 수업 못 가요/못 들어요.

Is 수업 the same as “class” and when would I use 강의?

수업 is the general word for a class/lesson session. Very common.
강의 is a “lecture” (university-style). You might say 강의에 출석하다 or 강의를 듣다 in a college context.
English loanword 클래스 exists but is less general; it’s used for branded courses, fitness classes, etc. In school contexts, 수업/강의 is more natural.