Verb Conjugation Roadmap: From Stem to Every Ending

Korean conjugation is scattered across dozens of ending pages, and met one at a time it can feel like an endless list of unrelated forms. It is not a list — it is a ladder, where each rung depends on the one below. This roadmap walks that ladder from the bottom: strip a verb to its stem, learn the one master rule that feeds everything, then add the polite present, the formal register, tense, the irregular predicates, and finally the connective and attributive endings. Climb it in order and new endings stop being new — they are just old machinery with a different tail.

This is a foundational climb, and it rewards patience: skip the harmony and contraction rungs and try to memorize surface forms, and the whole thing collapses at your first irregular verb. Take the steps in order; each assumes the last.

Step 1 — Stem vs ending

Every Korean verb and adjective cited in a dictionary ends in -다. Strip that -다 and what remains is the stem, the piece every ending attaches to: 가다 → 가-, 먹다 → 먹-, 예쁘다 → 예쁘-. Conjugation is nothing more than stem + ending. Start with stems and endings, how conjugation works, and the dictionary form -다, and settle the adjective point on action vs descriptive verbs and adjectives are verbs.

Step 2 — Vowel harmony: the master rule

This is the rung everything above depends on. When an ending begins with the 아/어 vowel, its shape is chosen by the stem's last vowel: if that vowel is ㅏ or ㅗ, the ending takes 아; for every other vowel, it takes 어; and 하다 is special, giving 해. Internalize this once and you can predict the present, the past, and half the connectives. Study vowel harmony 아/어 and the 아/어 selection reference.

Step 3 — The polite present 아요/어요 and its contractions

Now the everyday register: the polite present 해요체, formed with 아요/어요 by the harmony rule you just learned. The wrinkle is contraction — when a vowel-final stem meets 아/어, the two vowels merge: 가 + 아요 → 가요, 마시- + 어요 → 마셔요, and 하- → 해요. These merges are regular; learn the table, not the individual forms. Study the present 해요, vowel-stem contractions, the 하다 → 해 fusion, the ㅣ-glide contraction (마시 → 마셔), the 해요체 contractions, and keep the contraction table handy.

Step 4 — The formal 합니다체

The same stem takes a second register: the formal polite 합니다체, used in presentations, announcements, and with strangers of status. The rule is a clean vowel/consonant split — -ㅂ니다 after a vowel stem, -습니다 after a stem ending in a batchim. Study the formal present -ㅂ니다/-습니다, the 합니다체 overview, and the 합니다체 sheet.

Step 5 — Tense: past 았/었어요 and future 겠 / -(으)ㄹ 거예요

Tense reuses everything so far. The past is 았/었어요 — harmony-matched exactly like the present (갔어요, 먹었어요) and contracting the same way. The future/modal layer has two pieces: 겠 (intention, conjecture) and -(으)ㄹ 거예요 (plans, expectation). Study the past -았/었어요 with its harmony and contractions, then future 겠 and -(으)ㄹ 것이다, framed by the tense system overview and the reference sheets on past -았/었- and future 겠/-(으)ㄹ 것.

Step 6 — The irregular predicates

Here is where surface memorization breaks and the stem-plus-rule habit pays off. Seven stem-final letters behave irregularly before vowel endings — each is its own study page: ㅂ (덥다 → 더워요), ㄷ (듣다 → 들어요), ㅅ (짓다 → 지어요), 르 (모르다 → 몰라요), 으 (쓰다 → 써요), ㄹ (살다 → 삽니다), ㅎ (그렇다 → 그래요). Start with the irregular overview and which endings trigger irregularity, then take them one page each: ㅂ irregular, ㄷ irregular, ㅅ irregular, 르 irregular, 으-drop, ㄹ-stem, and ㅎ irregular. Consolidate with the irregular-vs-regular master table.

Step 7 — Connective endings

Once you can conjugate a single clause, endings that join clauses come next, and they attach to the same stems by the same vowel/consonant logic: -고 (and), -지만 (but), -아서/어서 (and-so/because), -(으)면 (if), -(으)니까 (since). Study the connectives overview and the core five: -고, -지만, -아서 (cause/sequence), -(으)면 (if), and -(으)니까 (since).

Step 8 — Attributive (relative) endings

The top rung, and the one place adjectives and action verbs finally split. To turn a clause into a noun-modifier, verbs take -는 (present), -(으)ㄴ (past), -(으)ㄹ (prospective); adjectives take -(으)ㄴ for their present. This is the only real difference between the two verb classes in the whole system. Study present relative -는, past relative -(으)ㄴ, prospective -(으)ㄹ, and the adjective side on attributive -(으)ㄴ and adjective -(으)ㄴ vs verb -는; consolidate with the attributive forms table.

The error this path exists to prevent

The one habit that derails everything is treating adjectives like English adjectives that need a copula. They do not — a Korean adjective is a verb and conjugates directly. Get this wrong and every descriptive sentence you build is malformed. See adjectives as English adjectives and, further up, irregular over- and under-application.

Key takeaways

• Conjugation is a ladder: stem → vowel harmony → present → formal → tense → irregulars → connectives → attributives, each rung built on the last.
• Vowel harmony (ㅏ/ㅗ → 아, else → 어, 하다 → 해) is the master rule feeding the present, past, and connectives — learn it before any surface form.
• Adjectives conjugate exactly like action verbs; the only split is the attributive endings at the very top.
• Learn the rules (harmony, contraction, irregular triggers), not the surface forms — that is what survives contact with the irregular verbs.