hoeui jungeneun hyudaepon sorireul kkeo juseyo.

Please turn off your phone’s sound during the meeting.

Breakdown of hoeui jungeneun hyudaepon sorireul kkeo juseyo.

• ~를: object particle
• ~는: topic particle
• 휴대폰: cell phone
• ~에: time particle
• 회의: meeting
• 소리: sound
• ~중: during
• ~주세요: please (polite request/imperative)
• 꺼 주다: to turn off (for someone)

Questions & Answers about hoeui jungeneun hyudaepon sorireul kkeo juseyo.

What does 회의 중에는 mean, and how is it built?

회의 중에는 means during the meeting / while the meeting is going on.
Breakdown:

• 회의 = meeting
• 중 = middle, in the midst of (used for during)
• -에 = time/place marker (here: at/in that time)
• -는 = topic/contrast marker
  So 회의 중에 = during the meeting, and 회의 중에는 adds a topic/contrast feel like as for during meetings (at least).

What nuance does -에는 add compared to just -에?

-에는 (really -에 + 는) often adds:

• topic framing: as for during the meeting…
• contrast (explicit or implied): during the meeting (not outside it)
  So 회의 중에 휴대폰 소리를 꺼 주세요 is a neutral time setting, while 회의 중에는… sounds a bit more like a rule or reminder.

Is 중에는 the same as 동안에는? How are they different?

They overlap, but the feel is slightly different:

• 중(에) = in the middle of / while actively happening (focus on the event being in progress)
• 동안(에) = for the duration of / throughout the time period (focus on the time span)
  A meeting is an event in progress, so 회의 중에(는) is especially natural for rules like phone etiquette.

Why does it say 휴대폰 소리 instead of 휴대폰을?

Because what you’re turning off is specifically the sound, not necessarily the whole phone.

• 휴대폰 소리 = cellphone sound (ringtone/notification sounds)
• 휴대폰을 꺼 주세요 would usually mean turn off the phone (power off), which is stronger than intended in many contexts.

What exactly does 소리 refer to here?

소리 literally means sound, and in this context it commonly means:

• ringtone
• notification sounds
• any audible alerts
  So it’s basically telling people to make their phone silent/quiet (though literally it says to turn the sound off).

How does 꺼 주세요 work грамmatically? Why 꺼?

The verb is 끄다 = to turn off (a switch, light, sound, etc.).
When conjugated, 끄다 becomes 꺼- (this is a common vowel change pattern):

• 끄다 → 꺼요 (polite present)
• request form: 꺼 주세요 = please turn it off (for me/us)
  -아/어 주세요 adds the nuance of please do it as a favor / please do it for us.

Why not say 끄세요 instead of 꺼 주세요?

Both can be translated as please turn it off, but the tone differs:

• 끄세요 = a more direct polite command/instruction
• 꺼 주세요 = a softer request (because of 주세요)
  In public notices or polite reminders, 꺼 주세요 often sounds more courteous.

Can the object particle 를 be omitted in 휴대폰 소리를?

In casual speech, yes, it can sometimes be dropped:

• 휴대폰 소리 꺼 주세요 (more casual/compact)
  But in signage, announcements, or careful polite speech, keeping 를 is common and clearer:
• 휴대폰 소리를 꺼 주세요 (standard/polite)

Is this sentence polite enough for announcements? What level is 주세요?

Yes—주세요 is polite and widely used in customer-facing situations.
Rough politeness scale for this kind of request:

• casual: 꺼 줘
• polite: 꺼 주세요
• more formal/polite: 꺼 주시기 바랍니다, 꺼 주시면 감사하겠습니다
  This sentence sits in the normal polite range (very common on signs).

How is 회의 pronounced? Is it 회-의 or blended?

In careful pronunciation, it’s close to 회-의 (two syllables). In fast speech it can sound somewhat blended, but learners usually do fine pronouncing it clearly as 회 / 의.
The key is that 의 can vary in pronunciation depending on position/word, but here 회의 is commonly said close to 회이 for many speakers.

Does spacing matter here (e.g., 꺼 주세요)? Could it be written differently?

Yes, spacing is standard as written:

• 회의 중에는 / 휴대폰 소리를 / 꺼 주세요
  주세요 is an auxiliary-like verb meaning please give (me/us), so it’s normally spaced: 꺼 주세요 (not usually 꺼주세요 in standard spacing).