Korean Pattern ~아/어서: How to Say "because / so (casual)"

Verb stem + 아/어서. Cause-and-effect. Less formal than ~기 때문에. Cannot use with commands/proposals.

The Rule

~아/어서 = "because / so (casual)" Verb stem + 아/어서. Cause-and-effect. Less formal than ~기 때문에. Cannot use with commands/proposals. This is one of the essential Korean grammar patterns. Mastering it unlocks the ability to express "because / so (casual)" naturally in conversation — something you'll need almost every day.

Why English Speakers Get It Wrong

In English, "because / so (casual)" is expressed with separate words (auxiliary verbs, modals). In Korean, ~아/어서 is a grammatical ENDING attached to the verb stem. You can't just translate word-by-word. The common mistake: trying to combine Korean words the way English does instead of attaching the pattern to the verb stem. Korean grammar works by stacking endings, not by adding separate helper words.

How It Works

Formation: Verb stem + 아/어서 Verb stem + 아/어서. Cause-and-effect. Less formal than ~기 때문에. Cannot use with commands/proposals. Step by step: 1. Take any verb (e.g., 가다 = to go) 2. Remove 다 to get the stem (가) 3. Add the pattern: 가아/어서 This works with virtually any Korean verb.

Real Examples

• 배가 아파서 못 갔어요. (baega apaseo mot gateoyo.) — "I couldn't go because my stomach hurt." • 만나서 반갑습니다. (mannaseo bangapseupnida.) — "Nice to meet you. (lit: Because we met, I'm happy.)"

Common Mistakes

❌ Trying to translate "because / so (casual)" word-by-word from English ✅ Use the pattern ~아/어서 attached to the verb stem → Korean expresses "because / so (casual)" as a single grammatical construction, not separate words. ❌ Forgetting vowel harmony or consonant rules ✅ Check if the verb stem ends in a vowel or consonant — the pattern may change form → Pay attention to the verb stem's final sound when attaching the pattern.

Quick Tip

Practice ~아/어서 with 5 verbs you already know. Write them out: • 가다 (go) → 가아/어서 • 먹다 (eat) → 먹아/어서 Repetition with familiar verbs builds the pattern into muscle memory. Once automatic, you can use it with ANY verb.

~아/어서 = "because / so (casual)"

Examples

배가 아파서 못 갔어요. — baega apaseo mot gateoyo. — I couldn't go because my stomach hurt.

만나서 반갑습니다. — mannaseo bangapseupnida. — Nice to meet you. (lit: Because we met, I'm happy.)