BareumPickThere is a moment most learners hit around six months in. You know the word 한국말. Someone says it to you and you do not recognise it, because what they said was 한궁말. You conclude that your listening is bad.
Your listening is probably fine. You were listening for something that nobody says.
Why the rules exist
Korean spelling is morphophonemic: it writes each meaningful piece of a word in its own fixed shape, so you can see that 꽃 in 꽃이 and 꽃밭 is the same flower. Pronunciation then smooths the joins between those pieces.
This is a feature, not a flaw — it makes reading and recognising words much easier. But it means the written form and the spoken form are related by rule rather than identical, and nobody can hold a conversation until they know the rules. The good news is that there are only about six, they apply without exception, and they are mechanical.
1. Liaison — the final consonant moves across
If a syllable ends in a consonant and the next one starts with a vowel, the consonant moves into the next syllable.
| Written | Pronounced | Meaning |
|---|---|---|
| 옷이 | 오시 | clothes (subject) |
| 밥을 | 바블 | rice (object) |
| 꽃이 | 꼬치 | flower (subject) |
| 한국어 | 한구거 | Korean language |
Learn this one first. Korean marks grammar with particles that begin with vowels — 이, 을, 에, 은 — so liaison fires in nearly every sentence you will ever hear. See the batchim guide for what happens to that consonant when no vowel follows.
2. Nasalisation — stops become nasals before a nasal
If ㄱ, ㄷ or ㅂ is followed by ㄴ or ㅁ, the stop turns into the nasal made in the same place.
| Written | Pronounced | Change |
|---|---|---|
| 한국말 | 한궁말 | ㄱ → ㅇ |
| 끝나다 | 끈나다 | ㄷ → ㄴ |
| 밥물 | 밤물 | ㅂ → ㅁ |
| 입문 | 임문 | ㅂ → ㅁ |
The logic is physical, not arbitrary: your soft palate has to open for the nasal, and it opens a fraction early, so the preceding stop comes out through the nose. Try saying 한국말 with a hard ㄱ and you will feel your mouth fighting you.
This rule is the single biggest reason spoken Korean does not match the page.
3. Tensification — plain consonants go tense after a stop
After an unreleased ㄱ, ㄷ or ㅂ, a following plain consonant becomes its tense counterpart.
| Written | Pronounced | Meaning |
|---|---|---|
| 먹고 | 머꼬 | eat and |
| 학교 | 학꾜 | school |
| 입구 | 입꾸 | entrance |
| 낯설다 | 낟썰다 | to be unfamiliar |
Note that you do not write the tense consonant and you do not choose it — it is forced. Learners often read 학교 carefully as hak-gyo and sound noticeably stiff, because the natural form is hak-kkyo.
4. Lateralisation — ㄴ and ㄹ merge into ㄹㄹ
When ㄴ and ㄹ meet in either order, both become ㄹ.
| Written | Pronounced | Meaning |
|---|---|---|
| 신라 | 실라 | Silla (the kingdom) |
| 설날 | 설랄 | Lunar New Year |
| 관리 | 괄리 | management |
5. Palatalisation — ㄷ and ㅌ before 이
When ㄷ or ㅌ is followed by 이, it shifts forward to ㅈ or ㅊ.
| Written | Pronounced | Meaning |
|---|---|---|
| 같이 | 가치 | together |
| 굳이 | 구지 | insistently |
| 붙이다 | 부치다 | to attach |
This one only applies across a grammatical boundary, which is why 밭이 becomes 바치 but a word like 티 inside a single morpheme keeps its ㅌ.
6. Aspiration — ㅎ combines with the next consonant
ㅎ does not survive next to a plain stop. The two merge into a single aspirated consonant.
| Written | Pronounced | Change |
|---|---|---|
| 좋고 | 조코 | ㅎ + ㄱ → ㅋ |
| 많다 | 만타 | ㅎ + ㄷ → ㅌ |
| 입학 | 이팍 | ㅂ + ㅎ → ㅍ |
And before a vowel, ㅎ simply disappears: 좋아요 is 조아요.
The order to learn them in
Not all six pay off equally. Ranked by how often they fire in ordinary speech:
- Liaison — every sentence with a particle
- Nasalisation — extremely common, and the main cause of failed listening
- Tensification — very common, and the main cause of sounding stiff
- Aspiration — common in verb endings
- Lateralisation — a small, fixed set of words
- Palatalisation — a small, fixed set of words
If you only ever learn three, learn the first three.
You can read this page in ten minutes and still apply none of it in conversation, because applying it in real time is a motor skill, not knowledge. The route that works is small amounts of reading aloud, every day, with someone correcting the joins — not more rules. The free guides on our home page include a printable version of this table, and our free pronunciation check tells you which of these you are already doing without noticing.
FAQ
Why is 한국말 pronounced 한궁말?
Because of nasalisation. The ㄱ at the end of 국 is followed by the ㅁ of 말, and a stop cannot be held directly before a nasal — it becomes the nasal made in the same place, so ㄱ turns into ㅇ. The same rule gives 끝나다 → 끈나다 and 밥물 → 밤물.
How many sound change rules does Korean have?
Six cover almost everything a learner meets: liaison, nasalisation, tensification, lateralisation, palatalisation and aspiration. There are smaller patterns beyond these, but these six account for the great majority of the gap between Korean spelling and Korean speech.
Are these rules optional or formal?
Neither. They are automatic and obligatory. A Korean speaker reading 학교 aloud says 학꾜 without deciding to, and pronouncing every letter as written sounds noticeably unnatural rather than careful or polite.
Why does Korean spelling not just match the pronunciation?
Because the writing system keeps each meaningful part of a word in a constant shape, so that 꽃 looks the same in 꽃이 and 꽃밭. That makes words easy to recognise in print, at the cost of a predictable set of rules between the written and spoken forms.