Learn Hardcore Japanese: yoru ha urusaku sinaide kudasai.

夜は marks the topic: “As for the night…” It frames the time period and often implies contrast (e.g., daytime might be different).
夜に simply marks time: “at night.” It’s neutral, just indicating when.
夜には adds emphasis like “especially at night” or “at least by night.”
All are possible; 夜は is common when stating a general rule or reminder.

Why is it うるさく and not うるさい?

うるさい is an i-adjective. To modify a verb (to say “noisily”) or to use with する, i-adjectives take the adverbial form 〜く.
So うるさい → うるさく. Then うるさくする means “to act in a noisy way / make (things) noisy.”
Saying うるさいしないでください is ungrammatical; adjectives can’t directly modify verbs without the 〜く form.

What does うるさくする literally mean, and is it natural?

Literally: “to make (something) noisy” or “to do (things) noisily.”
It’s perfectly natural and common for “behave in a noisy way.” Example: 授業中にうるさくしないで (“Don’t be noisy during class”).

Why is it しないでください, not しないください or なくてください?

What’s the difference between しないでください and just しないで?

しないでください is the standard polite request: “Please don’t…”
しないで alone is casual. It can be a softer plea in conversation (“Don’t do that”), or it can mean “without doing” when it connects to another clause (e.g., 食べないで寝た “slept without eating”).

Can I say うるさくないでください?

No. ないでください attaches to verbs, and うるさい is an adjective.
Use one of these:
- うるさくしないでください (use the verb する).
- うるさくならないでください (“please don’t become loud,” i.e., don’t get louder).
- Positive request alternative: 静かにしてください (“Please be quiet”).

Could I use the verb 騒ぐ instead? What’s the nuance difference from うるさい?

騒ぐ means “to make noise/be rowdy.” A very natural variant is 夜は騒がないでください (“Please don’t make a racket at night”).
うるさい describes the quality “noisy/annoyingly loud.” うるさくする focuses on behaving in a noisy manner. Both are fine; 騒ぐ can feel a bit more concrete.

How polite or strong is this sentence? What are alternatives?

Standard polite: 〜ないでください (your sentence).
Softer/formal request: 〜ないようにお願いします, 静かにお願いします, or signage-style 夜間はお静かに.
More polite, indirect: 〜ないでいただけますか / 〜ないでいただけると助かります.
Blunt command: 〜するな (e.g., うるさくするな, 騒ぐな). Very direct/rough.
Friendly tone add-ons: …くださいね (gentler), …くださいよ (insistent).

Who is the subject here? Why isn’t “you” stated?

Japanese often omits the subject when it’s obvious. Here, the implied subject is “you” (the listener/reader). Context supplies who is being asked not to be loud.

Why are there spaces in 夜はうるさくしないでください。? Do Japanese normally write like this?

No. Japanese normally doesn’t use spaces between words. The spacing here is for learners.
A natural written form would be: 夜は、うるさくしないでください。 (comma after the topic is optional but common).

Why is ください in kana and not the kanji 下さい?

When ください is the polite request auxiliary (V-て + ください / V-ないで + ください), it’s usually written in kana.
下さい as a standalone verb meaning “please give (me)” may be written with kanji (e.g., 水を下さい), though kana is also common. Style guides favor kana for the auxiliary.

Can I say 夜で or 夜では?

Generally no. で marks location/means, not time in this way. Use 夜に for “at night.”
夜では can appear in very specific contrastive frames but is not used to state time for a request like this. Stick with 夜は (topic) or 夜に (time).

What’s the difference between 夜, 晩, and 夜中 here?

夜: night in general; most standard for “at night.”
晩: evening; somewhat earlier than deep night. Less common in this kind of rule/request.
夜中: the middle of the night; emphasizes late-night hours. Example: 夜中はうるさくしないでください (“Please don’t be loud in the middle of the night”).

Why not うるさくてしないでください? What’s the difference between 〜く and 〜くて?

〜く is the adverbial form used to modify verbs (うるさくする = “do noisily”).
〜くて is the て-form for linking clauses/expressing cause (“it’s noisy and/so…”).
うるさくてしないでください doesn’t mean “don’t do it noisily”; it awkwardly tries to link “it’s noisy and…” to “please don’t do (it).” Use うるさくしないでください for “please don’t be noisy.”

What’s the grammar behind しないで?

する (to do) → negative plain: しない → negative て-form: しないで.
Then add ください to make a polite negative request: しないでください (“Please don’t do …”).
Note: 〜なくて is another negative connector, but not used with ください for requests.

Is there a more formal “without doing” alternative to 〜ないで?

Yes: 〜ずに (classical-style, more formal/written). With する, it becomes せずに.
Example for signage/hospitality: うるさくせずにお過ごしください (“Please spend your time without being noisy”).