The Secret of Irregular Words
In Korean, irregular words do not change their shape every time you use them.
The dictionary form (the stem) stays exactly the same in many situations. The change only happens when a specific type of ending is attached.
So, when you see an irregular word, do not immediately change it. First, look at the ending you want to add!
Before Consonants: No Change
When you attach an ending that starts with a consonant , the irregular stem usually keeps its original shape.
Endings like -고 (and) or -지만 (but) start with consonants. Because there is no vowel at the start of the ending, the stem stays the same.
Dictionary Form · Before a Consonant
듣다 · 듣고
춥다 · 춥지만
Before Vowels: The Change Happens
When you attach an ending that starts with a vowel , the irregular stem typically changes.
Endings like -아요/어요 or -(으)면 start with vowels (the placeholder ㅇ). This is when the irregular rule takes action!
Dictionary Form · Before a Vowel
듣다 · 들어요
춥다 · 추워요
Checking the Ending First
A common mistake is changing the stem before every ending. Remember to check the ending first!
Common Mistakes
(X) 음악을 들고 자요.
(O) 음악을 듣고 자요. (Before -고, there is no change!)
(X) 날씨가 춥어요.
(O) 날씨가 추워요. (Before -어요, it changes!)