gaein samusireun jeongmal joyonghaeyo.

은 is the topic marker. It marks 개인 사무실 as the thing the sentence is talking about.

So 개인 사무실은 정말 조용해요 is like:

• As for a private office, it’s really quiet
• or more naturally in English, A private office is really quiet

A common nuance of 은/는 is contrast or general commentary. Depending on context, it can sometimes suggest something like:

• Private offices are really quiet
  maybe compared with open offices, classrooms, cafés, etc.

Because 사무실 ends in a consonant, you use 은. If a noun ends in a vowel, you use 는.

In Korean, nouns often modify other nouns directly, without needing 의.

So:

• 개인 = individual, personal, private
• 사무실 = office
• 개인 사무실 = personal/private office

This is very common in Korean. It works a lot like English noun+noun combinations:

• school bus
• office chair
• coffee shop

If you said 개인의 사무실, that would sound more like an individual’s office or someone’s personal office, which is a different nuance.

In this sentence, private is often the most natural English idea.

개인 literally relates to the individual/personal side of something, but in combinations like 개인 사무실, it often refers to an office used by one person rather than a shared space.

So possible translations include:

• private office
• personal office
• individual office

Among these, private office is usually the most natural in everyday English.

정말 means really.

It adds emphasis:

• 조용해요 = It’s quiet
• 정말 조용해요 = It’s really quiet

It is not grammatically necessary. You can remove it and the sentence is still perfectly correct:

• 개인 사무실은 조용해요.

So 정말 just strengthens the statement.

Because 조용하다 is an adjective/descriptive verb in Korean, not a noun.

That means it does not use 이에요/예요, which are used after nouns.

Compare:

• 학생이에요 = (I am / he is / it is) a student
  → 학생 is a noun
• 조용해요 = (it is) quiet
  → 조용하다 is a descriptive verb/adjective

So:

• 사무실은 학생이에요 ❌
• 사무실은 조용이에요 ❌
• 사무실은 조용해요 ✅

The dictionary form is 조용하다.

It changes like this:

• 조용하다 → stem 조용하-
• add polite ending -아요
• 하 + 아요 contracts to 해요

So:

• 조용하다 → 조용해요

This happens with many 하다 words:

• 공부하다 → 공부해요
• 필요하다 → 필요해요
• 깨끗하다 → 깨끗해요

조용해요 is in the 해요 style, which is polite and very common in everyday conversation.

It is appropriate in many situations:

• talking to someone you don’t know well
• talking to coworkers
• talking to teachers or service staff in casual-polite situations

Other levels:

• 조용하다 = dictionary form
• 조용해 = casual/informal
• 조용해요 = polite everyday speech
• 조용합니다 = more formal, polite, and stiff

So this sentence sounds natural and polite for ordinary speech.

Korean works differently from English here.

In English, you usually need is:

• The office is quiet

But in Korean, words like 조용하다 already carry the meaning of to be quiet. So 조용해요 already means is quiet / are quiet depending on context.

That means Korean does not need a separate word exactly like English is in this sentence.

The sentence is:

• 개인 사무실은 = as for the private office
• 정말 = really
• 조용해요 = is quiet

So the order is basically:

topic + adverb + adjective

Korean often puts adverbs like 정말 before the word they modify:

• 정말 조용해요 = really quiet

This is very normal.

Usually 정말 goes before the adjective or verb it modifies, so 정말 조용해요 is the most natural placement.

You may also hear slight variations in speech for emphasis, but for learners, the safest pattern is:

• 정말 + adjective/verb

Examples:

• 정말 맛있어요 = It’s really delicious
• 정말 비싸요 = It’s really expensive
• 정말 조용해요 = It’s really quiet

Yes. Korean often leaves number unspecified unless it needs to be clear.

So 개인 사무실은 정말 조용해요 could refer to:

• a private office in general
• private offices as a type
• the private office already known from context

Korean does not always mark singular vs. plural the way English does. Context tells you which meaning is intended.

A simple pronunciation guide is:

• 개인 → gae-in
• 사무실은 → sa-mu-si-reun
• 정말 → jeong-mal
• 조용해요 → jo-yong-hae-yo

A few notes:

• 개인 has two syllables after 개: 개-인
• In 사무실은, the 실 links smoothly into 은, so it sounds like 시르은 in connected speech
• 조용해요 is pronounced smoothly, with 해요 sounding like hae-yo

You do not need to force an English-style stress pattern; Korean rhythm is more even.

In standard Korean, 은 is important here. Without it, the sentence sounds incomplete or unnatural in most situations.

So:

• 개인 사무실은 정말 조용해요 ✅
• 개인 사무실 정말 조용해요 △ possible in very casual, broken, or note-like speech, but not the normal full sentence

As a learner, it is best to keep 은 here.

Good question. Both can be possible in Korean, but the nuance changes.

• 개인 사무실은 정말 조용해요

  • topic/comment
  • As for private offices, they’re really quiet
  • can sound more general or contrastive

• 개인 사무실이 정말 조용해요

  • subject-focused
  • The private office is really quiet
  • can emphasize that this is the thing that is quiet

Very roughly:

• 은/는 = topic, comparison, general statement
• 이/가 = subject, identification, focus

In many beginner situations, either may be translated similarly in English, but the Korean nuance is different.