Korean 아/어/여 Conjugation: The Vowel Harmony Rule

You learn a shiny new verb, go to use it, and freeze on one tiny choice: 먹아요 or 먹어요? That fork — 아, 어, or 여 — shapes how almost every Korean verb becomes everyday speech. This beginner-friendly guide to Korean 아/어/여 conjugation shows you exactly which ending a stem takes, and why 오다 quietly becomes 와요.

How Korean 아/어/여 conjugation works

Every Korean verb in the dictionary ends in 다 (da). Chop off the 다 and you get the stem. To speak politely, you add one of three endings, and the stem's last vowel picks which one. This is vowel harmony: bright vowels attract 아, everything else takes 어, and 하다 verbs get a special 여.

When do you use 아요 vs 어요?

Look at the last vowel in the stem. If it is ㅏ or ㅗ — the two "bright" vowels — add 아요. For every other vowel, add 어요. That single check covers the vast majority of Korean verbs, so it is the first rule worth burning into memory.

Bright vowels ㅏ, ㅗ → 아요

Every other vowel → 어요

하다 verbs: the 여 group → 해요

하다 (to do) refuses to play by the 아/어 rule. It takes the special 여, and 하 + 여 always fuses into 해. This matters more than it looks, because hundreds of verbs are just a noun plus 하다: 공부하다 (study), 운동하다 (exercise), 사랑하다 (love). Learn one pattern, conjugate a thousand words.

Want the full tour of stems, negatives, and formal endings once this clicks? The Korean verb conjugation guide walks through the whole system step by step.

Hear the three groups

Tap each base verb to hear a native speaker say the dictionary form, then conjugate it out loud yourself. Listen for the group each one belongs to — 아, 어, or the 하다 special.

Why does 오다 become 와요? Vowel contractions

Here is the part textbooks rush past. When a stem ends in a vowel, that vowel and the 아/어 don't just sit next to each other — they merge. This is why 오다 becomes 와요 instead of 오아요, and it is the single biggest source of "wait, where did that come from?" moments.

Common 아/어/여 conjugation mistakes

That is the whole engine of Korean 아/어/여 conjugation: check the stem's last vowel (ㅏ/ㅗ → 아요, otherwise 어요), remember that 하다 becomes 해요, and let the vowel merges settle in with your ear. Get this one decision automatic and most present-tense speech falls into place.

Now try it: take five verbs you already know and say each one in 해요 form out loud — that is Korean 아/어/여 conjugation in action. Then keep going with the past tense (-았/었어요), which is built on this exact 아/어 stem, or drill the everyday verbs in Daily Routines where you'll use it most.