Learn Hardcore Japanese: watasi ha asita no kaigi ni syussekisimasu.

は marks the topic: As for me, …. It sets the frame of reference rather than emphasizing who is doing the action. Using が (私が明日の会議に出席します) highlights or contrasts the subject (It is I who will attend), which fits contexts like correcting someone or answering a who-question. In a neutral statement about your own plans, 私は… or simply omitting 私 is more natural than 私が….

Do I need to say 私 at all?

No. Japanese often omits pronouns when they’re understood from context. 明日の会議に出席します is perfectly natural and common. Use 私は… when you want to:

Set yourself as the topic for a new thread of conversation.
Contrast with others (私は出席しますが、田中さんは出席しません).
Avoid ambiguity in multi-person settings.

Why is の used between 明日 and 会議? Could I just say 明日会議?

の turns 明日 (tomorrow) into a modifier for 会議 (meeting): 明日の会議 = tomorrow’s meeting. You cannot say 明日会議 to mean the same thing. Alternatives:

明日の会議に出席します (modify the noun)
明日、会議に出席します (use 明日 as a time adverb, separated by a pause/comma)
明日は会議に出席します (make tomorrow the topic)

Why is the particle に used with 会議? Why not を or で?

出席する takes に to mark the event/occasion you attend; it’s like marking the target or occasion of presence.

会議に出席します = I will be present at the meeting.
を is not used here (会議を出席する is unnatural).
で marks the location where an action happens; with 出席する, we’re not describing an action happening at a place, but presence at an event. 会議で出席する is incorrect.
へ also sounds wrong here; stick with に for 出席する.

What’s the difference between 出席する and 参加する?

出席する: to attend/be present. Focus on presence/headcount. Common for classes, meetings, ceremonies, RSVP contexts.
参加する: to participate/take part. Emphasizes involvement or active participation. Common for events, projects, workshops, competitions. For a meeting, both can appear, but 出席 is standard/formal for attendance; 参加 can imply you’re taking part in the discussion/activity.

Is 会議に出る also correct? How does it differ?

Yes. 会議に出る literally means to go out/appear at the meeting and is common in everyday speech. Nuance:

会議に出席する: more formal/polished.
会議に出る: neutral/casual. In writing (especially business), 出席する is safer; in conversation, 出る is very natural.

Does 出席します mean future tense? How is the future expressed?

Japanese doesn’t have a dedicated future tense. The non-past form (します) covers present and future. Time expressions (e.g., 明日) or context tell you it’s future. So 出席します plus 明日 clearly means a future plan.

Why not say 明日に? When do you use に with time words?

Relative-day words like 今日, 明日, 昨日 usually don’t take に when used as time adverbs. So:

Natural: 明日、会議に出席します.
Unnatural: 明日に、会議に出席します. You can use に if adding another particle or nuance, e.g., 明日にはわかります (by tomorrow, we’ll know), where には adds contrast/limit. When modifying a noun, use の: 明日の会議.

How formal/polite is this sentence? What are alternatives?

出席します is polite (です/ます style), good for most workplace situations. Variants:

Plain: 出席する (casual or neutral writing).
Extra formal/humble (e.g., RSVP or to clients): 出席いたします.
Very casual: 明日の会議、出るよ / 出るね. Choose based on relationship and setting.

Can I change the word order?

Yes, Japanese allows flexible order for adverbials/topics, but keep the verb at the end and modifiers attached to their nouns. Natural variants:

明日は会議に出席します (tomorrow as topic)
会議には明日出席します (contrastive focus on the meeting)
私は明日、会議に出席します (pause after time) Avoid breaking noun phrases like 明日の会議 or moving the verb away from the end.

How do you pronounce the words? Is は pronounced wa?

私: わたし (watashi)
は (topic particle): pronounced wa
明日: あした (common), あす (more formal/businesslike), みょうにち (very formal/written)
の: の (no)
会議: かいぎ (kaigi)
に: に (ni)
出席します: しゅっせきします (shusseki shimasu; note the doubled consonant っ)

Is 出席します one word or two? What’s happening morphologically?

It’s a する-verb built from the Sino‑Japanese noun 出席 (attendance) + する (to do). In polite form, する becomes します. So:

Dictionary: 出席する
Polite: 出席します You can think of it as a single verb meaning attend, even though it’s morphologically noun + do.

How do I make negative, past, questions, or other common forms?

Negative (polite): 出席しません
Past (polite): 出席しました
Past negative (polite): 出席しませんでした
Question: 出席しますか
Volitional: 出席しましょう (let’s), or 出席しよう (plain)
Potential (can): 出席できます
Intention/plan: 出席するつもりです / 出席する予定です

How do I add contrast or emphasis with は elsewhere?

[ANSWERANSWER] Attach は to other phrases for contrast:

会議には出席しますが、懇親会には出席しません (I’ll attend the meeting, but not the social).
明日には出席します (by tomorrow/I will at least attend tomorrow), adding a contrastive/limiting nuance with には.

Are spaces normal in Japanese writing?

No. Standard Japanese doesn’t use spaces between words. The spaced version is for learners. Normally you’d write: 私は明日の会議に出席します。

How do I say I plan/intend to attend, or I won’t attend?

Plan/schedule: 明日の会議に出席する予定です.
Intention: 明日の会議に出席するつもりです.
Will not attend (polite negative): 出席しません.
Formal RSVP no: 欠席します / 欠席いたします (I will be absent).