In short

반말 (banmal, casual speech), grammatically 해체, is the intimate register you use with close friends, siblings and people clearly younger than you. The shortcut is simple: take your 해요체 form and drop the 요 - 가요 -> 가 (ga), 먹었어요 -> 먹었어 (meogeosseo). A few endings change shape (the copula, the future, “let’s”), and the pronouns switch too. Use it only where the relationship licenses it - defaulting to 반말 with a stranger or an elder is rude.

The rule

Step 1 - Drop 요 and you have 반말

For the vast majority of verbs and adjectives, 반말 is the 해요체 form minus 요. Everything you already learned about 아/어 vowel harmony and its contractions carries straight over.

해요체 form - 요 = 반말

• 가다 -> 가요 -> 가 (ga, go)
• 먹다 -> 먹어요 -> 먹어 (meogeo, eat)
• 하다 -> 해요 -> 해 (hae, do)
• 마시다 -> 마셔요 -> 마셔 (masyeo, drink)
• 있다 -> 있어요 -> 있어 (isseo, there is); 없다 -> 없어 (eopseo, there isn’t)
• Past: 갔어요 -> 갔어 (gasseo, went); 먹었어요 -> 먹었어 (meogeosseo, ate)

Step 2 - One form, three sentence types by intonation

Like 해요체, a single 반말 form does statement, question and command - only the intonation differs. There are no separate endings to learn here.

Verb stem + -아/어 = statement (flat), question (rising intonation), or command (falling intonation)

• 가. (ga.) - I’m going. / 가? (ga?) - Are you going? / 가! (ga!) - Go!

A more pointed question can add -니? or -냐? to the stem: 가니? (gani?), 먹니? (meongni?), 가냐? (ganya?). The two are not interchangeable in tone: -니? is the friendlier of the pair - typical of an adult speaking to a child, and used more by women - while -냐? sounds rougher and is common among young men.

Step 3 - The endings that change shape

Three high-frequency endings do not just drop 요; they take a special 반말 form.

• Copula: -(이)야, chosen by the noun’s 받침 - after a vowel -야 (의사야, is a doctor), after a 받침 -이야 (학생이야, is a student). Negative: 아니야 (aniya, is not).
• Future / probability: -(으)ㄹ 거야 - 갈 거야 (gal geoya, will go), 먹을 거야 (meogeul geoya, will eat).
• Propositive (“let’s”): -자 - 가자 (gaja, let’s go), 먹자 (meokja, let’s eat). This one has no 요 form at all; the polite equivalent is 가요 or 갈까요.

Softened requests still take -아/어 줘 (from -아/어 주세요): 도와줘 (dowajwo, help me), and prohibitions use -지 마 (from -지 마세요): 가지 마 (gaji ma, don’t go).

Step 4 - Switch the pronouns and the yes/no words

반말 comes with its own set of person words. The humble 저/제 belongs to polite speech; 반말 uses 나/내가.

• 나 (na, I) -> topic 나는 (naneun), subject 내가 (naega). Never *저는 … 가 - that pairs a humble pronoun with a casual ending and is a register clash.
• 너 (neo, you) -> topic 너는 (neoneun), subject 네가 (nega), colloquially pronounced and even written 니가 (niga) to keep it distinct from 내가.
• Yes: 응 (eung) or 어 (eo). No: 아니 (ani).

Step 5 - Calling someone in 반말

To get attention you say 야 (ya, hey). With a name you add a vocative particle chosen by the name’s 받침: after a vowel -야, after a 받침 -아.

• 민수 (vowel) -> 민수야 (Minsuya); 지혜 (vowel) -> 지혜야 (Jihyeya)
• 민혁 (받침) -> 민혁아 (Minhyeoga); 지훈 (받침) -> 지훈아 (Jihuna)

Step 6 - Who may use it, and the risk

반말 is licensed by age and closeness, and among adults it is normally mutual and agreed: people say 말(을) 놓다 (mareul nota, to drop formal speech) - “말 놓으세요” or “말 편하게 해” invites it. Until that happens, stay in 해요체. Use can also be asymmetric: an adult speaks 반말 down to a child, or a senior to a junior, while the other returns 존댓말 (polite speech). One-sided 반말 between adults reads as a power move. The safe default is always 해요체; drop into 반말 only once the relationship clearly allows it.

Note: the blunt written plain style you meet in books, diaries and headlines - -(느)ㄴ다, -아/어라 (한다체) - is a different paradigm, not spoken 반말. It is taught later in lesson 58.

Forms & patterns

Drop 요: the 해요체 -> 반말 conversion (statements):

The endings that change shape (copula chosen by 받침):

Sentence types from the 반말 form (가다, 먹다):

Pronouns, yes/no and address:

Examples

Common mistakes

• 저는 학교에 가. (Jeoneun hakgyoe ga.) -> 나는 학교에 가. (Naneun hakgyoe ga.) - 저 is the humble pronoun of polite speech; 반말 takes 나/내가. Mixing 저 with a casual ending is a register clash.
• 학생야. (Haksaengya.) -> 학생이야. (Haksaengiya.) - After a 받침 the casual copula is -이야, not -야. Bare -야 only follows a vowel (의사야).
• 여기 화장실이야? (Yeogi hwajangsiriya?) -> 여기 화장실 있어? (Yeogi hwajangsil isseo?) - Use 있어 for existence (“is there a…?”); 화장실이야? means “is it a bathroom?” (identity). This is the 있어 vs 이야 split.
• 가자요. (Gajayo.) -> 가자. (Gaja.) - -자 is already casual and takes no 요; there is no *-자요. To be polite, use 가요 or 갈까요 instead.
• 선생님, 뭐 해? (Seonsaengnim, mwo hae?) -> 선생님, 뭐 하세요? (Seonsaengnim, mwo haseyo?) - 반말 to someone older or senior is rude; keep 존댓말 upward, even when they use 반말 to you (asymmetric use).

Tips

• The one-move shortcut: drop 요. Almost every 반말 form is just your 해요체 form with 요 removed (먹었어요 -> 먹었어). Memorise only the three that resist it: the copula (-이야/-야, not *-이에), the future (-거야) and “let’s” (-자).
• 반말 is earned, not assumed. Never open with it to a stranger or an elder. Wait for the other person to say 말 놓으세요 / 말 편하게 해, or offer it yourself - until then 해요체 is always safe.
• It is often one-directional. Adults speak 반말 down to children and seniors to juniors, while the other side answers in 존댓말. Between peers it should be mutual; one-sided 반말 among adults sounds like a power play.
• Don’t confuse casual with plain-written. Spoken casual is 해 / 가; the -(느)ㄴ다 / -아/어라 you see in print is the separate 한다체 written style (lesson 58), not conversation.