Casual Ending -아/어 in Korean

In Brief

Korean casual speech commonly uses the same form as -아/어요 without 요: 가요 → 가, 먹어요 → 먹어, 해요 → 해. This style, called 해체, is natural with close friends, many family members, children, and people who have agreed to use 반말. It is not a default form for every informal situation: with a stranger, customer, teacher, older acquaintance, or senior colleague, keep 요 unless the relationship clearly allows otherwise.

Overview

The ending -아/어 is the basic everyday casual ending in Korean. It belongs to 해체, a speech level used when the speaker does not add politeness toward the listener. You will also hear the broader word 반말, “non-honorific” or casual speech. In everyday conversation, people often use 반말 and 해체 almost interchangeably, although 반말 describes the social style more broadly and 해체 is the grammatical speech level.

This is an A1 pattern because its form is simple once you know the polite ending -아/어요: in most cases, remove 요. The difficult part is social rather than grammatical. English can sound friendly and informal without changing every verb, but Korean regularly marks the speaker’s relationship to the listener in sentence endings. A grammatically perfect 먹어 can therefore sound warm to a close friend and disrespectful to a stranger.

Casual -아/어 is not only a “statement ending.” Depending on context and intonation (the rise and fall of your voice), the same form can make a statement, ask a question, or give a direct instruction. Learning the ending means learning both its shape and the relationship in which it belongs.

How It Works

The beginner rule: remove 요

If you already know the everyday polite form, the quickest conversion is:

Korean	English	Note
가요 → 가	go; am/is going	가 already ends in ㅏ
먹어요 → 먹어	eat; am/is eating	Remove 요
봐요 → 봐	see; watch	The contraction remains
마셔요 → 마셔	drink	마시어요 contracts to 마셔요, then loses 요
해요 → 해	do	하다 has the contracted form 해
있어요 → 있어	exist; have; stay	Remove 요

Do not normally begin with a dictionary form such as 먹다 and merely remove 다. That gives the verb stem (the part to which endings attach), 먹-, not a finished casual sentence. You still need -어: 먹다 → 먹어.

Forming -아/어 from the dictionary form

Remove -다 to find the stem. Then choose the vowel:

1. Use -아 when the final vowel of the stem is ㅏ or ㅗ.
2. Use -어 after other vowels.
3. 하다 becomes 해.
4. Apply the same contractions and common irregular changes used with -아/어요.

Dictionary form	Stem + ending	Casual form	English
앉다	앉 + 아	앉아	sit; am sitting
좋다	좋 + 아	좋아	be good; like
오다	오 + 아	와	come
먹다	먹 + 어	먹어	eat
읽다	읽 + 어	읽어	read
배우다	배우 + 어	배워	learn
마시다	마시 + 어	마셔	drink
공부하다	공부하 + 여	공부해	study

The English gloss changes with context because Korean does not build tense, person, and sentence type in the same way English does. 가 might mean “I’m going,” “Are you going?”, or “Go.” Korean often leaves the subject unstated when everyone knows who is being discussed.

Statements, questions, and direct instructions

In 해체, sentence type often depends on context and voice:

Korean	English	Typical delivery
지금 가.	I’m going now. / He’s going now.	Falling statement intonation
지금 가?	Are you going now?	Rising question intonation
지금 가!	Go now!	Firm command; can sound sharp
천천히 먹어.	Eat slowly.	Friendly instruction or invitation

Punctuation only represents the difference in writing. In speech, listen to intonation and the situation. Because a bare command can be strong, voice and wording matter: 앉아! may be an order, while a gently spoken 여기 앉아 can be a friendly “Sit here.”

Tense and other grammar still come before the casual ending

Removing 요 does not remove tense or the rest of the sentence pattern. The final polite element changes, while earlier grammar stays in place.

Polite	Casual	English
먹었어요	먹었어	ate; did you eat?
재미있었어요	재미있었어	was fun
갈 거예요	갈 거야	will go; am going to go
하고 싶어요	하고 싶어	want to do it
할 수 있어요	할 수 있어	can do it
안 가요	안 가	do not go; am not going

Notice that 갈 거예요 → 갈 거야 is not produced by deleting only 요. The polite copula-like ending 예요 corresponds to casual 야 here. Learn such common pairs as complete patterns.

Nouns: 이야 and 야

After a noun, casual “is” is 이야 after a consonant and 야 after a vowel. These are the casual counterparts of 이에요/예요.

Korean	English	Pattern
학생이야.	(I/you/he/she) am/is a student.	학생 ends in a consonant + 이야
친구야.	(He/she) is a friend.	친구 ends in a vowel + 야
이거 뭐야?	What is this?	Very common casual question
학생이 아니야.	(I/you/he/she) am/is not a student.	아니다 → 아니야

Examples in Context

The following examples show casual speech in relationships where it is already appropriate.

Korean	English	Note
나 이제 가.	I’m leaving now.	Statement to someone close
어디 가?	Where are you going?	Casual question
뭐 해?	What are you doing?	Extremely common between friends
밥 먹었어?	Did you eat?	Often also expresses care or starts a conversation
응, 먹었어.	Yeah, I ate.	응 is casual “yes/yeah”
이 영화 진짜 재미있어.	This movie is really good.	Descriptive verb in casual form
오늘 시간 있어?	Do you have time today?	있어? with rising intonation
잠깐 기다려.	Wait a moment.	Direct but normal in a close relationship
물 좀 마셔.	Have some water.	좀 can soften the suggestion
같이 공부해.	Study with me/us.	Context can make this an invitation or instruction
미안해.	I’m sorry.	Casual apology
괜찮아?	Are you okay?	Casual question
이거 내 거야.	This is mine.	Noun pattern 거야
나도 갈게.	I’ll go too.	-ㄹ게 signals the speaker’s intention or promise
내일 다시 전화할게.	I’ll call again tomorrow.	Casual promise to the listener

Common Mistakes

Using 반말 just because someone looks young

• Wrong: 어디 가? to an unfamiliar adult who appears younger than you
• Right: 어디 가요?
• Why: Apparent age alone does not create a close relationship. Polite -요 speech is the safer default with an adult you do not know.

Treating every casual English situation as Korean casual speech

• Wrong: 아메리카노 줘. to a café employee
• Right: 아메리카노 주세요.
• Why: English “Can I get an Americano?” may feel conversational, but Korean service encounters normally still use polite endings. 줘 can sound like a blunt demand when there is no close relationship.

Removing 다 and stopping there

• Wrong: 나 밥 먹.
• Right: 나 밥 먹어.
• Why: 먹- is only the stem. Add -어 to make the normal casual form. A few clipped styles exist, but they are not the beginner pattern.

Forgetting contractions

• Wrong: 친구가 오아.
• Right: 친구가 와.
• Why: 오 + 아 contracts to 와, just as 와요 does in polite speech. Other common forms include 보아 → 봐, 주어 → 줘, and 마시어 → 마셔.

Assuming a period makes a form neutral

• Wrong assumption: 가. is always a harmless “I’m going.”
• Right understanding: It can be a statement or a command, depending on context and delivery.
• Why: Subjects are often omitted, and 해체 relies heavily on intonation. A firm 가! means “Go!” and can sound forceful.

Mixing casual endings into an otherwise polite exchange accidentally

• Wrong: 네, 알겠어요. 내일 보내. to a supervisor
• Right: 네, 알겠어요. 내일 보낼게요. or 내일 보내겠습니다.
• Why: One casual ending can abruptly change the social tone. Keep the speech level consistent until you intentionally switch.

Usage Notes

When is casual speech appropriate?

Common settings include close friends who use 반말 with one another, siblings, couples, many parent-child interactions, speech to young children, and private self-talk. It also appears widely in lyrics, social-media captions, diaries, slogans, and dialogue in fiction. Those written uses do not mean you should address an unfamiliar reader or person the same way.

Age matters in Korean, but it is not the only factor. Familiarity, role, workplace rank, family custom, and personal preference all matter. Two adults of the same age may quickly agree to speak casually; another pair may continue using -요 for a long time. A younger speaker may use 반말 with an older close friend only after the older person permits it, and some close friends still choose polite speech.

Useful phrases around switching include 말 놓으세요 (“You can speak casually to me”) and 우리 말 놓을까요? (“Shall we speak casually?”). As a learner, you do not need to rush the switch. Continuing with -요 may sound slightly reserved, but it is much safer than choosing 반말 too early.

Casual does not mean emotionless or impolite in itself

Within the right relationship, 잘 잤어? (“Did you sleep well?”), 밥 먹었어?, and 조심해 (“Take care”) can sound affectionate. The same grammatical level can also carry anger when spoken sharply. The ending marks the relationship; vocabulary, intonation, and context carry much of the emotional tone.

Words also change with the speech level

Do not focus only on the final 요. Casual conversations often use 응 instead of polite 네, and speakers may choose casual address terms or names. Conversely, inserting 네 does not make a casual verb polite: 네, 알았어 still ends in casual speech. A natural exchange usually keeps endings and response words aligned.

Beyond the Basics / Advanced Use

You do not need to master these points at A1, but they explain forms you will hear often.

해체 has many endings, not only -아/어

Casual speech includes endings that express intention, suggestion, reaction, or background information. Examples include 갈게 (“I’ll go”), 가자 (“Let’s go”), 가지 마 (“Don’t go”), 가네 (“Oh, [someone] is going”), and 가는데 (“I’m going, but/so…” or “As for going…”). They belong to the same broad non-polite style, but each ending has its own meaning. Do not try to turn every polite sentence casual by deleting its last syllable mechanically.

반말 and honorifics are separate dimensions

Korean can mark respect for the person being discussed with the honorific marker -(으)시-, while using a casual ending toward the listener. In a family, for example, someone might say 할머니 주무셔? (“Is Grandma sleeping?”) to a sibling. 주무시다 respects Grandma, while -어? is casual toward the sibling. This combination is natural in the right setting, but beginners should not take it as permission to address Grandma casually.

Switching levels can carry meaning

Speakers sometimes move briefly from polite speech to 반말 to signal sudden closeness, irritation, authority, or dramatic emphasis. Friends may also jokingly use very formal speech with each other. Such switching is socially expressive, not random. Until you can read the relationship confidently, consistency is the better strategy.

Written plain style is different

Korean explanatory writing, news, essays, and factual narration often use -다 forms such as 한국어는 재미있다. This is commonly called the plain or declarative written style and should not be confused with conversational 해체 재미있어. Both lack 요, but they serve different purposes and are not interchangeable in ordinary conversation.

Practice Tips

1. Convert familiar pairs aloud. Make a two-column list such as 가요–가, 먹어요–먹어, 해요–해, 봤어요–봤어, and 갈 거예요–갈 거야. Say the polite form first, then imagine the same message to a close friend.
2. Practice three intonations with one form. Record 지금 가., 지금 가?, and 지금 가! Listen for a falling statement, a rising question, and a firm instruction. This trains meaning, not just spelling.
3. Label the relationship in every example. Before repeating a line from a drama, ask who is speaking to whom. Copying 뭐 해? is useful only if you also notice why those characters can use 반말.

Related Concepts

• Prerequisite: Polite Ending -아/어요 — learn the everyday polite forms and their contractions before removing 요.