Korean Verb Conjugation Basics

Mastering verb conjugation is your gateway to forming complete sentences and expressing yourself in Korean. Unlike many European languages, Korean verbs follow a logical, pattern-based system that, once understood, becomes highly predictable. This overview will equip you with the foundational skills to conjugate verbs for tense, politeness, and formality, enabling you to start communicating effectively.

Understanding the Dictionary Form and Verb Stems

Every Korean verb starts in its dictionary form, which always ends with the syllable 다. For example, 가다 (to go), 먹다 (to eat), and 하다 (to do). To conjugate a verb, you must first identify its stem. You find the stem by simply removing the 다 ending. Thus, the stem of 가다 is 가-, and the stem of 먹다 is 먹-. This stem is the unchanging core to which you will attach various grammatical endings. Think of the stem as the verb's root identity, and the endings as accessories that modify its meaning for time and social context. This process is consistent across virtually all verbs, making it a reliable first step in sentence construction.

Conjugating for Present, Past, and Future Tenses

Korean indicates time through specific endings attached to the verb stem. The most common and versatile set of endings is the polite informal style, which is perfect for everyday conversations.

• Present Tense: You add -아요 or -어요 to the verb stem. The choice depends on vowel harmony. If the last vowel in the stem is ㅏ or ㅗ, you use -아요. Otherwise, you use -어요.
• 가다 (stem: 가-, last vowel ㅏ) becomes 가요.
• 먹다 (stem: 먹-, last vowel ㅓ) becomes 먹어요.
• 하다 (stem: 하-) is an exception and contracts to 해요.

• Past Tense: You add -았어요 or -었어요 using the same vowel harmony rule. This ending combines the past tense marker -았- or -었- with the polite -어요.
• 가다 becomes 갔어요 (가- + -았어요 contracts to 갔어요).
• 먹다 becomes 먹었어요.
• 하다 becomes 했어요.

• Future Tense: A common and simple future expression uses -ㄹ 거예요 or -을 거예요. If the stem ends in a vowel, add -ㄹ 거예요. If it ends in a consonant, add -을 거예요.
• 가다 becomes 갈 거예요.
• 먹다 becomes 먹을 거예요.
• 하다 becomes 할 거예요.

These tense endings allow you to place actions in time clearly and correctly.

Navigating Politeness and Formality with Key Endings

Korean society places great importance on respect and hierarchy, which is directly reflected in verb endings. You have already learned the polite informal ending -아요/-어요, which is used in most daily interactions with acquaintances, colleagues, and those of similar or slightly higher status. It is polite yet friendly.

For formal situations like news broadcasts, military commands, public speeches, or when showing high respect to someone much senior, you use the formal polite ending -ㅂ니다/-습니다. The rule is straightforward: if the verb stem ends in a vowel, add -ㅂ니다. If it ends in a consonant, add -습니다.

• 가다 (vowel stem) becomes 갑니다.
• 먹다 (consonant stem) becomes 먹습니다.
• 하다 becomes 합니다.

Crucially, the tense is applied before this formal ending. For past tense, you add -았- or -었- to the stem, then attach -습니다. For example, 가다 in past formal is 갔습니다 (가- + -았- + -습니다).

The Liberating Simplification: No Person or Number Agreement

One of the most learner-friendly aspects of Korean grammar is that Korean verbs do not change for person or number unlike European languages such as Spanish, French, or English. The conjugated verb 가요 can mean "I go," "you go," "he goes," "we go," or "they go." The same form 먹었어요 means "I ate," "you ate," "she ate," etc. The subject of the sentence is often inferred from context or explicitly stated with a pronoun or noun at the beginning. This eliminates a huge layer of memorization required in other languages, allowing you to learn one conjugation pattern that works for every subject.

Common Pitfalls

1. Misapplying Vowel Harmony: The most frequent error is using the wrong present tense ending (-아요 vs. -어요). Always check the last vowel of the verb stem. For the verb 보다 (to see), the stem is 보- and the last vowel is ㅗ, so it correctly conjugates to 봐요, not 보어요.
2. Overusing the Formal Style: Beginners sometimes default to -ㅂ니다/-습니다 for everything, which can sound stiff and distant in casual settings. Reserve the formal style for truly formal occasions, and use -아요/-어요 for general polite conversation.
3. Forgetting to Use the Stem: Always remove the 다 before adding endings. A common mistake is trying to attach an ending directly to the dictionary form, resulting in incorrect constructions like 가다요 instead of the correct 가요.
4. Ignoring Contractions and Irregulars: Some verbs undergo sound changes. For instance, 듣다 (to listen) has a stem ending in ㄷ that changes to ㄹ before a vowel-ending suffix, becoming 들어요. While this is a concise overview, being aware that these patterns exist will help you recognize them as you advance.

Summary

• All Korean verbs start in the dictionary form ending in 다; conjugation begins by removing 다 to isolate the verb stem.
• Tense is created by adding specific endings: -아요/-어요 for present, -았어요/-었어요 for past, and -ㄹ 거예요/-을 거예요 for future, following vowel harmony rules.
• Politeness is controlled by endings: use -아요/-어요 for polite informal speech and -ㅂ니다/-습니다 for formal polite situations, attaching them to the appropriately tensed stem.
• A major simplification is that Korean verbs do not conjugate for person or number; one form works for "I," "you," "he," "we," and "they."
• Success hinges on accurately applying vowel harmony rules and choosing the correct politeness level for your social context.