Learn Hardcore Korean: chuwoseo changmuneul dadayo. - It’s cold, so I close the window.

It’s a connective ending attached to the adjective 춥다 to express cause/effect. Here 추워서 means “because it’s cold,” linking the reason (cold) to the action (closing the window).

How do you pronounce 추워서?

It’s pronounced roughly as “chwoo-uh-suh.” The IPA transcription is [tɕʰuːʌsʌ], with a slight reduction in the vowel sounds.

Why is there no subject like “I” or “it” in the sentence?

Korean often omits subjects when they’re clear from context. In 추워서 창문을 닫아요, the speaker implies “I” (or “we”) without stating it explicitly.

What does 창문을 닫아요 mean literally, and why is 을 used?

창문 means “window,” and 을 marks it as the direct object of the verb 닫다 (“to close”). 닫아요 is the polite present-tense form, so the phrase literally means “(I) close the window.”

What is the dictionary form of 닫아요, and how is it conjugated?

The dictionary form is 닫다. To form the polite present tense, drop -다 from the stem 닫- and add -아요 (because the stem vowel is ㅏ, you attach -아요).

What politeness level does -아요 indicate, and can it be changed?

-아요 is polite informal speech (존댓말). You can switch to more formal by using -습니다 → 닫습니다, or to casual by dropping -요 → 닫아.

Why does Korean typically put the verb at the end of the sentence?

Korean follows a subject–object–verb (SOV) word order. The main verb almost always comes last, with subjects and objects (and other modifiers) appearing before it.

Could you use -니까 instead of -어서? Would 추우니까 창문을 닫아요 be correct?

Yes. -니까 also means “since/because,” so 추우니까 창문을 닫아요 is grammatically correct. -니까 is often considered slightly more formal or assertive than -어서, but in everyday conversation both are acceptable.