The Common Pattern of Irregulars
In previous lessons, you learned about the ㄷ, ㅂ, and ㅅ irregulars. Instead of treating them as completely separate rules to memorize, notice their common structure!
When you attach an ending that starts with a consonant (like -고 or -지만 ), the original bottom consonant (받침) stays exactly the same.
However, when you attach an ending that starts with a vowel (like -아요/-어요 or -(으)면 ), the irregular change happens.
Comparing the Forms at a Glance
Let's look at the core examples side by side. Notice how -고 keeps the original shape, while -어요 and -(으)면 trigger the changes.
Base Form · + 고 · + 어요 · + (으)면
듣다 · 듣고 · 들어요 · 들으면
춥다 · 춥고 · 추워요 · 추우면
짓다 · 짓고 · 지어요 · 지으면
Why "-(으)면" Causes Changes
Endings like -(으)면 (if/when) and -(으)세요 (please do) start with the vowel 으 . Because they start with a vowel, they trigger the irregular changes just like -아/어요 does.
ㄷ becomes ㄹ: 듣다 → 들으면
ㅂ becomes 우: 춥다 → 추우면
ㅅ disappears: 짓다 → 지으면
The Golden Rule and Common Mistake
A common mistake is applying the irregular change everywhere, even before consonants.
Common Mistake
Incorrect: 음악을 들고 숙제해요.
Correct: 음악을 듣고 숙제해요.
Always look at the first letter of the ending you want to attach. If it is a consonant like 고 , keep the original dictionary shape!