The Three Paths of Conjugation
When you want to use a Korean verb or adjective in polite everyday conversation, you must first drop the dictionary ending -다 .
What remains is the stem . To finish the word, you need to add an ending. For polite present sentences, you will choose one of three paths: -아요 , -어요 , or -해요 .
How do you know which one to choose? You simply look at the last vowel of the stem. It does not matter what the word means or whether it is a verb or an adjective. The vowel decides everything.
When to use -아요
The ㅏ and ㅗ Rule
If the very last vowel in the stem is ㅏ or ㅗ , you add -아요 .
Dictionary Form · Stem · Vowel · Polite Form
찾다 · 찾 · ㅏ · 찾아요
좋다 · 좋 · ㅗ · 좋아요
잡다 · 잡 · ㅏ · 잡아요
When to use -어요
The Default Path
If the last vowel is anything other than ㅏ or ㅗ, you add -어요 . This includes vowels like ㅓ, ㅜ, ㅣ, ㅡ, and others. You can think of -어요 as the basic default ending for most words.
Dictionary Form · Stem · Vowel · Polite Form
먹다 · 먹 · ㅓ · 먹어요
읽다 · 읽 · ㅣ · 읽어요
길다 · 길 · ㅣ · 길어요
The Special Case of 하다
하다 becomes 해요
There is one very common exception that ignores the vowel rule entirely. Any verb or adjective that ends in 하다 (to do) will completely change to 해요 .
공부하다 → 공부해요
요리하다 → 요리해요
운동하다 → 운동해요
Whenever you see 하다, do not worry about the vowels. Just change it directly to 해요.
Focus on the Last Syllable
When a stem has more than one syllable, learners sometimes look at the wrong vowel. You must only look at the final syllable right before the -다 that you dropped.