karaoke no kositu de maiku wo tukau.

No. Japanese is normally written without spaces:

カラオケの個室でマイクを使う。

The spaces here are just for learners, so it is easier to see the parts of the sentence:

• カラオケ
• の
• 個室
• で
• マイク
• を
• 使う

の connects nouns. In this sentence, it shows that 個室 is related to カラオケ.

So:

• カラオケ = karaoke
• 個室 = private room
• カラオケの個室 = a private room for karaoke / a karaoke private room

You can think of A の B as something like:

• B of A
• A’s B
• B related to A

Here, the most natural English translation is a private karaoke room or a private room at a karaoke place.

で marks the place where an action happens.

Since 使う means to use, the sentence needs a location where that action takes place:

• 個室で使う = use (it) in a private room

So で answers the question Where is the action done?

Compare:

• 学校で勉強する = study at school
• 部屋で食べる = eat in the room
• カラオケの個室でマイクを使う = use a microphone in a karaoke private room

This is a very common question.

In many cases:

• で = the place where an action happens
• に = a destination, point in time, or place of existence

Here, 使う is an action, so で is the natural choice.

• 個室でマイクを使う = use a microphone in the private room

If you used に, it would sound unnatural in this sentence.

A simple way to remember it:

• action happening somewhere -> で
• going to somewhere / existing somewhere -> に

Examples:

• 部屋で話す = talk in the room
• 部屋にいる = be in the room
• 部屋に行く = go to the room

を marks the direct object of the verb.

The direct object is the thing that receives the action.

So:

• マイク = microphone
• 使う = to use
• マイクを使う = to use a microphone

Other examples:

• 本を読む = read a book
• 水を飲む = drink water
• 日本語を話す = speak Japanese

So in this sentence, を shows that the microphone is the thing being used.

Japanese sentences usually put the verb at the end.

This is one of the biggest word-order differences from English.

English:

• Use a microphone in a karaoke private room.

Japanese:

• カラオケの個室でマイクを使う。
• literally: In a karaoke private room, microphone use

A rough pattern is:

• [place] で [object] を [verb]

This final-verb structure is very normal in Japanese.

使う is the dictionary form (plain form) of the verb.

You often see dictionary form:

• in vocabulary lists
• in example sentences
• in casual speech
• when no special politeness is being shown

使います is the polite form.

So:

• マイクを使う = use a microphone / will use a microphone
• マイクを使います = use a microphone / will use a microphone (polite)

Both are correct, but they have different levels of formality.

Japanese often leaves out the subject when it is obvious, unimportant, or understood from context.

So this sentence could mean things like:

• I use a microphone in a karaoke private room.
• You use a microphone in a karaoke private room.
• People use microphones in karaoke private rooms.

Without context, the subject is simply unspecified.

This is very normal in Japanese. You do not need to include a subject in every sentence the way you often do in English.

Katakana is often used for:

• loanwords from other languages
• foreign names
• sound effects
• emphasis in some cases

Here:

• カラオケ = karaoke
• マイク = microphone / mic

These are both words commonly written in katakana.

By contrast:

• 個室 and 使う are native/Japanese-Sino vocabulary, so they are written with kanji and hiragana.

Not exactly.

• 部屋 means room in a general sense.
• 個室 means private room, often emphasizing that it is separated from others.

So 個室 is more specific.

In a karaoke context, 個室 is very natural because Japanese karaoke places often have separate private rooms for each group.

So:

• 部屋 = room
• 個室 = private room

Yes. Japanese plain present form often covers both:

• a general/habitual meaning
• a future meaning, depending on context

So マイクを使う can mean:

• use a microphone
• will use a microphone

Examples:

• habitual: At karaoke, people use microphones in private rooms.
• future: We’ll use a microphone in a private karaoke room.

The exact meaning depends on context.

Yes, it is grammatical and understandable, but by itself it feels a little like a simple example sentence rather than a full real-life statement.

That is because there is no topic or subject, and no extra context.

In actual conversation, you might often hear something like:

• カラオケの個室でマイクを使います。 = We/I use a microphone in a karaoke private room.
• カラオケの個室でマイクを使う。 = plain/casual version

So the sentence is fine, but it feels a bit like a textbook example unless it appears in a larger context.