From 먹다 to 먹어요 — how Korean verbs conjugate

Every Korean verb in the dictionary ends in -다, and nobody ever says it that way. This is the rule that gets you from one to the other.

The dictionary form is not a form you can say

Look up eat and you get 먹다; look up go and you get 가다. That -다 is a citation ending — how Korean lists a word, not how anyone uses it. A Korean verb never appears bare, so the dictionary has to pick some ending, and -다 is the one it picked. Take it off and what is left is the stem. Everything below attaches there.

Note the last one. Korean adjectives take verb endings, so 좋다 conjugates exactly like 먹다 and there is no second system to learn for is good, is expensive, is tired.

ㅏ or ㅗ takes 아요. Everything else takes 어요.

Look at the last vowel in the stem. If it is ㅏ or ㅗ, the ending is -아요. Any other vowel takes -어요. That is the whole branch.

The last vowel, not the first. 가르치다 has an ㅏ in it, but the stem is 가르치 and its last vowel is ㅣ, so it falls on the 어요 side — 가르쳐요.

하다 becomes 해요 — the one irregular worth memorising

하 ends in ㅏ, so the rule predicts 하아요. The real form is 해요. It is irregular and it is the only irregularity you have to memorise here — but it earns its keep, because Korean builds new verbs by bolting 하다 onto a noun.

When the stem ends in a vowel, the two vowels merge

This is the part learners actually get wrong. Korean will not leave two vowels side by side across this join — they contract, and the contraction is compulsory, not a casual-speech option.

Say each one with the vowels kept apart and you can hear why it collapsed. Nothing here is arbitrary — it is what speech does to a vowel sequence, frozen into the spelling.

The past tense is the same rule with ㅆ in the middle

Take the present form you just built, drop the 요, add a ㅆ under the last syllable, put 어요 back. Every contraction you already made carries straight over.

That is the shape. What the past tense means — including why 먹었어요 covers both I ate and I have eaten — belongs to the tense article, not this one.

One note on scope. A group of stems change shape themselves before an ending: the ㅂ, ㄷ, ㅅ, 르, 으 and ㅎ irregulars. 춥다 gives 추워요, not 춥어요. They get their own article; for now just recognise them — if the rule above builds a form your dictionary does not list, you have hit one, so look it up instead of guessing.

Common mistakes

• Saying the dictionary form. 저는 먹다 is not a sentence. The 다 comes off before anything else happens.
• Keeping 다 and adding to it. 먹다요, 가다요. Same fix — 다 goes first.
• 공부하아요. Every 하다 verb goes to 해요, with no exceptions: 공부해요.
• Not contracting. 가아요, 오아요, 마시어요. All understandable, all forms nobody uses.
• Judging by the first vowel of the stem. The last one decides. 가르치 → 가르쳐요, never 가르차요.
• Dropping the 요 by accident. 먹어 without it is 반말 — not a grammar error but a different level of politeness, which the speech-levels article covers.

How to practise

The rule takes ten minutes to learn and months to become usable, because at speaking speed you do not have time to work it out. What closes that gap is running a handful of verbs through the forms aloud until the shape arrives before the reasoning does.

Take 가다, 먹다, 마시다 and 하다, and say each as present then past in a row — 가요 갔어요, 먹어요 먹었어요, 마셔요 마셨어요, 해요 했어요. The sets below are built from video sentences, so every line in them is one of these forms already at work.

Practice this

• 56 Days x 10 Useful Korean Sentences (Basic) 560
• Easy, Useful Korean Expressions 500 (Basic) 512

All guides

• Korean word order: the verb always comes last
• 은/는 vs 이/가 — the particle that trips everyone
• Speech levels: 반말, 해요체, 합쇼체
• Honorifics: 시, 님, and words that change entirely
• Counting things: why 하나 becomes 한
• Past, present, future — and 겠 for what you assume
• Joining sentences: 고, 서, 지만, 니까
• How to actually shadow Korean