gaseupgireul teureo bonikka bangi deol geonjohaeseo mokdo deol apasseo.

It combines two pieces:

• 틀어 보다 = to try turning something on / to turn it on and see what happens
• -니까 = when, since, after doing and noticing

So 틀어 보니까 has the feeling of:

• when I turned it on
• after I tried turning it on
• once I turned it on, I found that...

It is not just a plain sequence. It usually suggests that the speaker did something and then learned or noticed the result.

In Korean, 틀다 is commonly used for devices that you run or switch on, especially things like:

• 에어컨을 틀다 = turn on the air conditioner
• 히터를 틀다 = turn on the heater
• 라디오를 틀다 = turn on the radio
• 가습기를 틀다 = turn on the humidifier

So even though 틀다 has other meanings in other contexts, here it means to turn on / run the device.

A learner may also know 켜다 for turn on. That is also a very common verb, but 틀다 is especially natural with appliances that operate continuously or produce air/sound.

Because 가습기 is the thing being turned on, so it is the object of 틀다.

• 가습기를 틀다 = turn on the humidifier

Here, -를 is the object marker.

If you used 가습기가, that would make humidifier the subject, which would not fit this verb in this sentence.

덜 means less.

It is used to say that something happens to a smaller degree than before or than expected.

Examples:

• 덜 춥다 = be less cold
• 덜 아프다 = hurt less
• 덜 건조하다 = be less dry

It is basically the opposite of 더 = more.

Because it describes two different things:

• 방이 덜 건조해서 = the room was less dry
• 목도 덜 아팠어 = my throat also hurt less

The first 덜 describes the room’s dryness. The second 덜 describes the amount of throat pain.

In English, we might also naturally repeat less:

• the room was less dry, so my throat hurt less too

Because 건조하다 is a descriptive verb/adjective, and 방 is the thing that is dry.

So:

• 방이 건조하다 = the room is dry

Here 방 is the subject of the descriptive state, so -이/가 is used.

You use -을/를 for a direct object, but 건조하다 does not take a direct object here.

-아서/어서/해서 often connects two clauses and can mean:

• so
• because
• and then, depending on context

Here it gives a reason/result relationship:

• 방이 덜 건조해서 목도 덜 아팠어
• because the room was less dry, my throat hurt less too

So -해서 links the room being less dry with the throat hurting less.

도 means also / too / even.

So 목도 덜 아팠어 means:

• my throat also hurt less
• my throat hurt less too

The 도 adds the idea that not only was the room less dry, but the throat too showed a good result.

Also, in Korean, 도 often replaces another particle. So underneath, this is basically:

• 목이 덜 아팠어 = my throat hurt less

but with 도 added for emphasis:

• 목도 덜 아팠어 = my throat hurt less too

Because Korean often leaves out information that is obvious from context.

So even though English often says:

• my throat
• I turned on the humidifier

Korean can naturally omit those if the listener can easily understand them.

In this sentence:

• the person who turned on the humidifier is understood
• the throat is understood to be the speaker’s throat

This kind of omission is extremely common in Korean.

Korean often expresses body pain by making the body part the subject.

So:

• 목이 아프다 = the throat hurts / I have a sore throat
• 머리가 아프다 = the head hurts / I have a headache
• 배가 아프다 = the stomach hurts / I have a stomachache

This is very natural Korean grammar.

So 목도 덜 아팠어 literally works like:

• the throat also hurt less

but in natural English we usually say:

• my throat hurt less too

아팠어 is casual, non-polite speech.

The dictionary form is:

• 아프다 = to hurt, to be sore

Past tense:

• 아팠어 = hurt / was sore

If you want the polite version, you would say:

• 아팠어요

So the full sentence in polite speech would be:

• 가습기를 틀어 보니까 방이 덜 건조해서 목도 덜 아팠어요.

It can be understood both ways, but the nuance is usually:

• I turned it on and then noticed the result
• after trying it, I found that...

So -아/어 보니까 often carries a small sense of trying something out and discovering what happened.

That is a little richer than a simple time marker like when. It suggests experience plus observation.

Yes. For example:

• 가습기를 트니까 방이 덜 건조해서 목도 덜 아팠어.

That would mean something like:

• when/since I turned on the humidifier, the room was less dry, so my throat hurt less too

Compared with that, 틀어 보니까 sounds a bit more like:

• I tried turning on the humidifier, and then I realized...

So 보다 adds a slight trial/experience/discovery feeling.

Good question. Both are possible, but they focus on slightly different things.

• 덜 건조해서 = because the room was less dry
• 덜 건조해져서 = because the room became less dry

The given sentence focuses on the resulting state of the room. It does not need to explicitly say became because that change is already easy to infer from the context.

So the original sentence sounds very natural and smooth.