Learn Hardcore Korean: ga-eureneun danpungi areumdawoyo. - In autumn, the fall foliage is beautiful.

가을 means “autumn” or “fall.” The particle -에 marks a time or place (“in autumn”), while -에는 is -에 + 는, combining the time/location marker -에 with the topic marker 는. So 가을에는 literally means “as for in autumn,” adding a slight emphasis or contrast (“when it’s autumn…”).

Why is the subject marked as 단풍이 instead of 단풍은 or no particle at all?

The particle 이/가 marks the grammatical subject of the sentence, focusing on what is beautiful. Using 단풍이 indicates “it’s the autumn leaves that are beautiful.” If you used 단풍은, you’d be setting “leaves” as the topic, which can imply a contrast (“As for leaves, they’re beautiful, but…”). Omitting the particle isn’t standard here because Korean typically requires a subject or topic marker for clarity.

What exactly does 단풍 mean?

단풍 refers to the colorful foliage of deciduous trees in autumn, often translated as “autumn leaves,” “fall foliage,” or “maple leaves.” It’s the general term for leaves turning red, orange, and yellow in the fall season.

How do we get 아름다워요 from the dictionary form 아름답다?

아름답다 is an adjective meaning “to be beautiful.” It’s a ㅎ/ㅂ-irregular adjective ending in -ㅂ. To conjugate in polite present tense:

Drop -다 → 아름답-
The ㅂ changes to 우 before vowel endings → 아름다우-
Add -요 for polite style → 아름다워요

Why did the speaker choose 아름다워요 instead of the more formal 아름답습니다?

Korean has multiple politeness levels:

-아름다워요 is polite informal (해요체), used in everyday conversation or friendly contexts.
-아름답습니다 is polite formal (합쇼체), often used in news reports, presentations, or when speaking to large audiences.
Here, 아름다워요 sounds warm and natural for casual speech.

Could we replace 아름답다 with 예쁘다 and say 가을에는 단풍이 예뻐요? Would the meaning change?

Yes, you can say 가을에는 단풍이 예뻐요. The nuance changes slightly:

아름답다 (beautiful) feels more poetic or grand, often used for landscapes, art, or profound beauty.
예쁘다 (pretty) is more casual and light, often used for people, small objects, or cute things.
Both are correct, but 아름답다 suits the majestic feel of autumn foliage better.

Is it possible to say 가을에 단풍이 아름다워요 without -는, and would that be wrong?

You can say 가을에 단풍이 아름다워요. It’s grammatically correct; it simply uses -에 (time marker) without the topic nuance -에는. The meaning “In autumn, the leaves are beautiful” stays the same, but you lose the slight emphasis or contrast that -에는 provides.

How would you express the same idea more casually, perhaps with friends?

In very casual speech you might say:

가을에 단풍 예쁘다! (“Autumn leaves are pretty!”)
가을에는 단풍 진짜 예쁘지? (“In autumn the leaves are really pretty, right?”)
Here you drop the polite -요 ending and add slangy particles (-지?, 진짜) to sound more familiar.