hoeuiga kkeutnago naseo chinguege jeonhwaharyeogo haeyo.

Because 끝나다 means to end / to be finished and is an intransitive verb. That means the meeting is treated as the thing that ends by itself:

• 회의가 끝나다 = the meeting ends
• 회의를 끝내다 = to end the meeting

So in this sentence, the speaker is saying:

• After the meeting ends, I’m going to call my friend

If you said 회의를 끝내고 나서, it would mean after ending the meeting or after finishing the meeting, which puts more focus on someone actively ending it.

It is used because 회의 is the subject of 끝나다.

• 회의가 끝나다 = the meeting ends

With 끝나다, the thing that finishes takes 이/가, not 을/를, because it is not a direct object.

Compare:

• 회의가 끝났어요. = The meeting ended.
• 회의를 끝냈어요. = I ended the meeting.

This is a very common verb pair in Korean:

• 끝나다 = to end, to be over
• 끝내다 = to finish something, to bring something to an end

Both can connect actions, but -고 나서 more clearly means after doing X, then Y.

So:

• 끝나고 나서 친구에게 전화하려고 해요 = After the meeting ends, I’m going to call my friend
• 끝나고 친구에게 전화하려고 해요 = also possible, but slightly simpler and less emphatic

-고 나서 often stresses that the second action happens after the first one is completed.

Examples:

• 숙제를 하고 나서 잘 거예요. = I’ll sleep after doing my homework.
• 밥을 먹고 나서 공부했어요. = I studied after eating.

It can look repetitive at first, but it is a fixed and common pattern:

• Verb stem + -고 나서

It literally has the feeling of do X and then afterward do Y. Native speakers use it very naturally.

For example:

• 집에 가고 나서 쉬었어요. = After going home, I rested.
• 수업이 끝나고 나서 만나요. = Let’s meet after class ends.

So even though -고 and 나서 both suggest sequence, together they form a standard grammar pattern.

Yes, 친구한테 is also natural here.

Both 에게 and 한테 can mean to when talking about a person:

• 친구에게 전화하다
• 친구한테 전화하다

The main difference is tone:

• 에게 = a bit more neutral or slightly more formal
• 한테 = more conversational

In everyday speech, 친구한테 전화하려고 해요 is very common.

You may also see:

• 친구께 = honorific to someone deserving respect

So you would not usually use 께 for friend, unless there is a special reason.

-려고 하다 means to intend to, to be planning to, or to be about to do something.

So:

• 전화해요 = I call / I’m calling
• 전화할 거예요 = I will call
• 전화하려고 해요 = I’m planning to call / I intend to call

This sentence is about the speaker’s intention, not just a future fact.

So the nuance is:

• 회의가 끝나고 나서 친구에게 전화하려고 해요. = After the meeting ends, I’m planning to call my friend.

It sounds a little softer and more like a personal plan.

It comes from:

• 전화하다 = to make a phone call / to call
• verb stem: 전화하-
• -려고 하다 attached to the stem

So:

• 전화하 + 려고 하다
• contracted in pronunciation/writing as 전화하려고 하다

Then polite present form:

• 전화하려고 해요

This pattern is used with action verbs:

• 먹으려고 해요 = I’m planning to eat
• 보려고 해요 = I’m planning to see/watch
• 공부하려고 해요 = I’m planning to study

This is because the ending attaches to the verb stem, not to the dictionary form.

• dictionary form: 전화하다
• stem: 전화하-

Then add -려고 하다:

• 전화하- + -려고 하다
• 전화하려고 하다

This is normal for 하다 verbs.

More examples:

• 운동하다 → 운동하려고 해요
• 청소하다 → 청소하려고 해요
• 공부하다 → 공부하려고 해요

So nothing irregular is happening here.

Korean word order is more flexible than English, but this sentence uses a very natural order:

• 회의가 끝나고 나서 = after the meeting ends
• 친구에게 = to my friend
• 전화하려고 해요 = I plan to call

A common default pattern is:

time/context + person/location + verb

You could rearrange some parts if the context is clear, for example:

• 친구에게 회의가 끝나고 나서 전화하려고 해요.

This is still understandable, but the original version sounds more natural and neutral.

In Korean, the verb usually comes at the end, so that part is the least flexible.

Yes. These are very similar:

• 회의가 끝나고 나서 친구에게 전화하려고 해요.
• 회의가 끝난 후에 친구에게 전화하려고 해요.

Both mean after the meeting ends.

The difference is mostly stylistic:

• -고 나서 = very common in everyday speech
• -ㄴ/은 후에 = also common, but can sound a little more formal or written

So both are correct, but -고 나서 feels very natural in conversation.

해요 is the polite, everyday speech style.

The full verb here is 하려고 해요, which comes from 하려고 하다 in the polite present form.

This style is appropriate in many normal conversations. Depending on the level of politeness, you could also say:

• 전화하려고 합니다 = more formal
• 전화하려고 해 = casual, plain/informal
• 전화하려고 해요 = polite everyday style

So the sentence is polite but not overly formal.

Yes. Korean very often omits subjects when they are obvious from context.

English usually needs:

• I’m going to call my friend after the meeting ends.

But Korean can simply say:

• 회의가 끝나고 나서 친구에게 전화하려고 해요.

The listener normally understands that the speaker means I from the verb ending and context.

This is one of the most common differences between Korean and English.

In this sentence, yes, it means to call or to make a phone call.

• 친구에게 전화하다 = to call a friend

A useful point is that Korean often uses a noun + 하다 structure:

• 전화 = phone call
• 전화하다 = to make a phone call

So literally it is something like do a phone call, but in natural English you just translate it as call.

Common examples:

• 엄마에게 전화했어요. = I called my mom.
• 나중에 전화할게요. = I’ll call later.