Learn Hardcore Korean: jeoneun gonghangeseo chekeu-ineul haeyo.

저 is the first-person pronoun “I.”
-는 is the topic particle, marking “I” as the topic of the sentence.
Together, 저는 means “as for me” or simply “I” when you’re making a statement about yourself.

Is it necessary to include 저는 here, or can I drop it and just say 공항에서 체크인을 해요?

In Korean, you can often omit the topic or subject if it’s clear from context.
– With 저는: you explicitly introduce “I.”
– Without it: 공항에서 체크인을 해요 still means “(I) check in at the airport,” assuming the listener knows you’re the subject.
Dropping the topic makes the sentence more natural in casual or well-understood situations.

What does 공항에서 mean, and what role does -에서 play here?

공항 means “airport.”
-에서 is the location-of-action particle.
– It tells you where the action (checking in) happens.
So 공항에서 literally means “at (the) airport” in the sense of “where I check in.”

What’s the difference between 공항에서 and 공항에?

-에서 marks the place where an action occurs.
-에 can mark a static location (“at”) or a destination (“to”).
– 공항에서 체크인을 해요 = I check in at the airport.
– 공항에 가요 = I go to the airport.
If you used 공항에 체크인을 해요, it would sound like “I check in to/at the airport” but with the nuance of -에 it’s less natural for expressing where the action takes place.

Why do we say 체크인을 해요? Can’t we just use 체크인 or say 체크인해요 without a particle?

– 체크인 is a noun borrowed from English (“check-in”).
– To turn it into a verb in Korean, you add 하다 (to do).
Form 1 (joined): 체크인하다 → polite present 체크인해요 (no object marker).
Form 2 (separated): 체크인 + -을 (object marker) + 하다 → 체크인을 해요.
Both are correct. When separated, you treat 체크인 as the direct object (“do the check-in”).

What does the ending -요 in 해요 indicate?

The -요 ending makes the verb polite and neutral (often called “polite informal”).
– You use it in everyday conversation with strangers or in customer service.
It’s less formal than -ㅂ니다/-습니다 but more formal than the plain style (no ending) used among close friends.

How would I say “I am checking in” to emphasize that the action is happening right now?

You’d use the progressive form -고 있다:
공항에서 체크인하고 있어요.
Literally, “At the airport, (I) am doing check-in.”

How would I make this sentence more formal, for example in an announcement or to a customer at the counter?

Switch to the formal polite ending -습니다:
저는 공항에서 체크인합니다.
Or in an even more direct customer-service style, you might see:
공항에서 체크인하시기 바랍니다. (“Please check in at the airport.”)

Why is the verb 해요 placed at the very end of the sentence?

Korean follows a subject-object-verb (SOV) word order.
– You typically list the subject/topic first, then place adverbials or objects, and finish with the verb.
That’s why 저는 (subject) → 공항에서 (location) → 체크인을 (object) → 해요 (verb).