How to Conjugate 잠그다 (to lock): regular-ㅡ Pattern

ㅡ-stem with preceding vowel ㅏ. ㅡ drops, previous syllable's vowel decides: 잠(ㅏ) → 잠가요.

The Rule

ㅡ-stem with preceding vowel ㅏ. ㅡ drops, previous syllable's vowel decides: 잠(ㅏ) → 잠가요. 잠그다 follows the regular-ㅡ irregular pattern. This means the verb stem changes when certain endings are added. Don't worry — once you learn this pattern, it applies to many other verbs too.

Why English Speakers Get It Wrong

English verb conjugation is relatively simple — "I eat, he eats, I ate." Korean is more complex because the verb ending changes based on politeness level, tense, AND the verb stem's final vowel or consonant. The regular-ㅡ pattern is especially tricky because the stem itself changes. English irregular verbs (go→went) change unpredictably, but Korean irregular verbs follow learnable PATTERNS. Once you know the regular-ㅡ rule, you can predict how all regular-ㅡ verbs behave.

How It Works

Stem: 잠그 Polite present (해요체): 잠가요 Polite past: 잠갔어요 Polite future: 잠글 거예요 Formal (합쇼체): 잠급니다 Negative: 안 잠가요 Notice how the stem "잠그" changes in some forms. This is the regular-ㅡ pattern in action.

Real Examples

• 잠가요 (jamgayo) — "lock (polite present)" • 잠갔어요 (jamgateoyo) — "lock (past)" • 잠글 거예요 (jamgeur geoyeyo) — "will lock (future)" • 잠급니다 (jamgeupnida) — "lock (formal)" • 안 잠가요 (an jamgayo) — "don't lock"

Common Mistakes

❌ 잠그어요 (jamgeueoyo) ✅ 잠가요 (jamgayo) → ㅡ drops. Previous vowel is ㅏ → 아요 ending: 잠가요. ❌ Using the casual form (잠그어/아) in formal situations ✅ Use 잠급니다 when speaking to elders, at work, or in official settings → Mixing up politeness levels is one of the most noticeable mistakes foreigners make in Korean.

Quick Tip

Start by mastering the 해요체 (polite) form: 잠가요. This is the form you'll use 90% of the time in daily life. Once it's automatic, add the past (잠갔어요) and future (잠글 거예요) to your toolkit. For regular-ㅡ verbs, make a list of 5 common ones and practice all their forms. The pattern will click after repetition.

잠그다: 잠가요 (present) / 잠갔어요 (past) / 잠글 거예요 (future)

Examples

잠가요 — jamgayo — lock (polite)

잠갔어요 — jamgateoyo — lock (past)

잠글 거예요 — jamgeur geoyeyo — will lock

잠급니다 — jamgeupnida — lock (formal)

안 잠가요 — an jamgayo — don't lock