hotel jigwoni gojang nan jeongureul baro bakkwo jwosseoyo.

이/가 marks the subject of the sentence, so 호텔 직원이 means the hotel employee/staff member is the one who did the action.

If you used 직원은, it would sound more like you are introducing or contrasting the staff member as a topic, such as As for the hotel staff, they changed it right away. In this sentence, 이/가 is the more neutral choice.

호텔 직원 means hotel employee or hotel staff member.

Korean often does not mark plural unless it is important, so 직원 can sometimes be understood generally. In this sentence, it most naturally sounds like one hotel staff member changed the bulb, but English may still translate it more generally as the hotel staff depending on context.

를 is the object marker. It marks the thing directly affected by the verb.

So in this sentence:

• 호텔 직원이 = the hotel employee is the subject
• 전구를 = the light bulb is the object
• 바꿔 줬어요 = changed it for someone

In other words, the employee did the action, and the bulb is what got changed.

고장 난 comes from the verb 고장 나다, which means to break down or to stop working.

To modify a noun in Korean, a verb changes into an attributive form. Here:

• 고장 나다 → 고장 난
• 고장 난 전구 = the bulb that has broken down / the broken bulb

So even though it looks adjective-like in English, it is built from a verb in Korean.

Because 고장 난 describes the bulb as already being in the broken state.

• 고장 나는 전구 would mean a bulb that breaks down or a bulb that is breaking, which does not fit the situation well here.
• 고장 난 전구 means a bulb that has broken down, which is exactly the idea needed before replacing it.

So this is the natural form for the broken light bulb.

The standard spacing is 고장 난.

That is because it comes from a verb phrase modifying a noun:

• 고장 나다 = to break down
• 고장 난 전구 = a broken bulb

In everyday writing, many people also write 고장난, but the standard written form is 고장 난.

Here 바로 means right away, immediately, or promptly.

바로 can have several meanings depending on context, such as:

• immediately
• directly
• exactly
• right

In this sentence, because it describes when the employee changed the bulb, the meaning is right away.

바꿨어요 simply means changed/replaced it.

바꿔 줬어요 adds the idea that the person did it for someone’s benefit. The helper verb 주다 often carries the sense of doing something for someone.

So:

• 바꿨어요 = changed it
• 바꿔 줬어요 = changed it for me/us/the guest

In this sentence, 줬어요 makes the action sound more like a service or favor provided to the speaker or the relevant person.

In Korean, the beneficiary is often left unstated if it is obvious from context.

Here, 바꿔 줬어요 usually implies the hotel employee changed the bulb for me/us/the guest. Korean often omits pronouns when they are understood.

If you wanted to say it explicitly, you could add something like:

• 저에게 바꿔 줬어요 = changed it for me
• 우리에게 바꿔 줬어요 = changed it for us

But in natural conversation, leaving it out is very common.

It comes from:

• 바꾸다 = to change, replace
• 주다 = to give; as a helper verb, to do for someone

Step by step:

• 바꾸다 → 바꿔
• 바꿔 주다 = to change it for someone
• 바꿔 줬어요 = did change it for someone

줬어요 is the contracted spoken form of 주었어요, and it is completely normal in everyday Korean.

Yes, 바꿔 줬어요 is polite because it ends in -어요. It is appropriate in many everyday situations.

However, it does not use the honorific marker -시- for the subject. If you want to show extra respect toward the hotel employee, you could say:

• 호텔 직원이 고장 난 전구를 바로 바꿔 주셨어요.

That sounds more respectful toward the person who did the action.

So the difference is:

• 바꿔 줬어요 = polite
• 바꿔 주셨어요 = polite and honorific toward the subject

Korean is generally a subject-object-verb language, so the verb usually comes at the end.

This sentence follows that pattern:

• 호텔 직원이 = subject
• 고장 난 전구를 = object
• 바로 = adverb
• 바꿔 줬어요 = verb

In English, we say The hotel employee changed the broken bulb right away, with the verb in the middle. In Korean, it is normal for the main action to appear at the end.