Learn Hardcore Japanese: asita ha ryou de ibento wo kaisaisimasu. - Tomorrow we will hold an event at the dorm.

The particle は marks the topic. 明日は means “as for tomorrow,” often with a slight contrast (not today, but tomorrow).
With time words like 明日, you can also drop the particle and just say 明日、寮で…. That’s very common and neutral.
Don’t use 明日に here to mean “on tomorrow” with this kind of verb; time words like 明日/今日/来週 usually don’t take に when they modify the whole sentence. Use either 明日、 or 明日は.

Why is は pronounced “wa” here?

When は is used as the topic particle, it’s pronounced “wa” for historical reasons. Inside words it’s “ha” (e.g., はな hana “flower”), but as the topic particle it’s “wa” (e.g., 私は watashi wa).

How do you read 明日, and does the reading change the tone?

あした: most common in everyday speech.
あす: slightly more formal or announcement-like.
みょうにち: very formal/written. In this sentence, because 開催します sounds formal, あす fits well in announcements. In casual speech, you’d likely say あした.

What exactly does 寮 mean?

寮 (りょう) is a dormitory—student housing or a company dorm. It can be a residence hall on campus or housing provided by an organization.

What does で after 寮 do? How is it different from に?

で marks the place where an action happens. 寮で開催します = “We’ll hold it at the dorm.”
に marks existence or destination. With existence verbs you can say:
- 寮でイベントがあります (event takes place at the dorm) or
- 寮にイベントがあります (an event exists at/in the dorm). Both are used with subtle nuance differences, but with an action verb like 開催します, you use で.

Why is イベント marked with を? Could I use が instead?

イベントを開催します uses を because 開催する is a transitive verb: you “hold” an event as the direct object.
Use が when the event is the subject of an intransitive verb or passive:
- イベントが開催されます (The event will be held.)
- イベントがあります (There will be an event.)

What nuance does 開催します have? Are there simpler or more casual options?

開催します is formal/official (“to hold an event/meeting”).
Alternatives:
- 行います: formal “carry out/hold,” very common in announcements.
- 開きます: “hold/open (a meeting/party/class),” a bit less stiff than 開催.
- します／やります: casual (“do/put on an event”).
- 実施します: formal “implement,” used for tests, measures, campaigns.
- あります: neutral existence (“There will be an event”). Choose based on formality and whether you want to emphasize hosting (開催/行う) or mere occurrence (ある).

Who is the subject here? It’s not stated.

Japanese often omits the subject when it’s clear from context. 開催します implies “we/our organization will hold [it]” if that makes sense in context. To make it explicit:

学生課が寮でイベントを開催します。 (The Student Affairs Office will hold…)
For a subject-neutral announcement, use passive: イベントが寮で開催されます。

Is the word order fixed? Can I move things around?

Word order is flexible, but common order is Time > Place > Object > Verb:

Natural: 明日は寮でイベントを開催します。
Also fine: 明日、寮でイベントを開催します。 (no topic particle)
Acceptable but less typical: 寮で明日イベントを開催します。 (time usually comes first)
Putting 明日 at the very end is uncommon in formal writing, though in speech you might hear “…開催します、明日” for emphasis.

Could I say 明日のイベントは寮で開催します?

Yes. 明日のイベントは寮で開催します。 means “As for tomorrow’s event, it will be held at the dorm.” Use の to let a time word modify a noun (イベント). Don’t say 明日の寮で…; “tomorrow’s dorm” doesn’t make sense.

Is イベントをします okay instead of イベントを開催します?

イベントをします is natural and more casual (“do an event”).
イベントを開催します／行います is the standard for formal notices, flyers, or official emails. Choose based on tone.

How polite is 開催します? When would I use いたします?

開催します: standard polite; good for most announcements.
開催いたします: extra-polite/humble (business, customer-facing notices).
開催する: plain form (neutral/informal narrative).

Why are there spaces between words? Do I need the comma?

Japanese normally doesn’t use spaces. The standard writing is:

明日は寮でイベントを開催します。 A comma after the time phrase is optional but common:
明日は、寮でイベントを開催します。

Can I drop particles in casual speech?

Sometimes, yes:

明日、寮でイベントする。 (drop を by switching to する)
You’ll also see headline-style compressions like イベント開催します, but in full sentences イベントを開催します is safer and more natural.

What’s the difference between saying “We will hold an event” and “There will be an event”?

Host-focused (we’re organizing): 明日は寮でイベントを開催します／行います。
Occurrence-focused (it’s happening, subject neutral): 明日は寮でイベントがあります。 or 明日は寮でイベントが開催されます。 Use the host-focused version if you want to emphasize responsibility/agency; use the occurrence-focused version for neutral announcements.