The Disappearing ㅡ Vowel
When a verb or adjective stem ends in the vowel ㅡ , it typically goes through a special change before endings like -아요 or -어요 .
The basic rule is simple: when ㅡ meets a vowel like 아 or 어 , the ㅡ disappears completely. This makes the pronunciation much smoother.
Short Words (No preceding vowel)
If a stem is very short and has no other vowel before the ㅡ , such as 쓰다 or 크다 , it defaults to the -어요 ending.
How it works
First, drop the ㅡ .
Then, add 어 .
쓰다 → ㅆ + 어요 → 써요
크다 → ㅋ + 어요 → 커요
Longer Words (Looking at the preceding vowel)
For words with more than one syllable, like 바쁘다 or 예쁘다 , you have to look at the vowel right before the ㅡ to decide between 아 and 어 .
Choosing 아 or 어
If the vowel before ㅡ is ㅏ or ㅗ , choose 아 . (바쁘다 → 바빠요 )
If the vowel before ㅡ is anything else, choose 어 . (예쁘다 → 예뻐요 )
Summary Comparison
Let's compare the most common words side by side to see the pattern.
Dictionary Form · Conjugated Form
쓰다 · 써요
크다 · 커요
바쁘다 · 바빠요
예쁘다 · 예뻐요
Notice how the ㅡ is completely gone in all of these conjugated forms.
Common Mistake: Keeping the ㅡ
A very common beginner mistake is trying to keep the ㅡ and simply attaching -어요 next to it.
Wrong: 바쁘어요, 쓰어요
Right: 바빠요, 써요
Always remember to drop the ㅡ first before combining the sounds!