Learn Hardcore Korean: seunggaekdeuri annae deseukeu ape isseoyo. - The passengers are in front of the information desk.

Without 들, 승객이 would mean “a passenger (as subject),” and without 이, 승객들 could be a plural noun in any role, but not explicitly marked as subject.

What does 안내 데스크 mean, and why is it written as two words?

안내 데스크 is a Konglish compound meaning information desk.

안내 comes from Sino-Korean roots meaning “guidance” or “information.”
데스크 is borrowed from English desk.

You’ll often see it with or without a space (안내데스크), but treating it as two words highlights the Korean + English parts.

What does 앞에 mean, and when should I use it?

앞 means “front.”
-에 is the location particle indicating where something is located.

Together, 앞에 means “in front of (something).” Use it whenever you describe being or placing an object/person in front of another object/person.

Other common location phrases:
• 뒤에 (“behind”)
• 옆에 (“beside/next to”)
• 위에 (“on top of”)
• 아래에 (“underneath”)

Why must I add -에 to 앞? Can’t I just say 안내 데스크 앞 있어요?

Korean relies on particles to show grammatical roles. In an existential sentence (there is/are), the pattern is:
[Location] + 에 + 있다/있어요

Without -에, 안내 데스크 앞 is just a noun phrase (“the front of the info desk”) with no role.
Adding -에 marks it as the place where the existence verb applies.

Hence, 안내 데스크 앞에 있어요 is grammatical, while 안내 데스크 앞 있어요 is not.

What does 있어요 convey here?

있다 is a versatile verb meaning “to exist” or “to have.” In this sentence it expresses existence/location:
[Subject] + [Place에] + 있다 → “(Subject) is located at (place).”

Forms of 있다:

Dictionary (base) form: 있다
Polite present: 있어요
Formal polite: 있습니다
Casual (intimate): 있어

You can negate it with 없다 → 없어요 (“there isn’t/aren’t”).

How can I adjust the sentence’s level of politeness?

Change the verb ending (and optionally use honorifics):
• Formal polite: 승객들이 안내 데스크 앞에 있습니다.
• Polite (standard): 승객들이 안내 데스크 앞에 있어요.
• Casual: 승객들이 안내 데스크 앞에 있어.

If you want to honor the passengers further, use the honorific subject marker 께서 and the honorific verb 계시다:
승객들께서 안내 데스크 앞에 계십니다.

Can I switch the word order to 안내 데스크 앞에 승객들이 있어요?

Yes. Korean has relatively free word order as long as particles stay attached:
• 승객들이 안내 데스크 앞에 있어요. (default S-V order)
• 안내 데스크 앞에 승객들이 있어요. (focus on location)

Avoid dropping particles or splitting them from their nouns.

Is it always necessary to use 들 to make a noun plural?

Not always. Korean often relies on context for plurality.

승객 can mean “passengers” if the situation is clear.
들 provides explicit plurality to remove ambiguity.

Use 들 when you want to be clear that there’s more than one, especially with animate nouns (people, animals).