Assume one thing – the head is upside down – and every consonant fits the mouth.
正音의 발음 해부도 — 목구멍이 위, 입술이 오른쪽 아래.
1. What you were taught
If you have taken even one Hangul lesson, you have heard this story. King Sejong designed the consonants in 1443 by drawing the mouth. Every textbook repeats the same five pictures:
- ㄱ (g/k) – the root of the tongue blocking the throat
- ㄴ (n) – the tip of the tongue touching the upper gum
- ㅁ (m) – the shape of the lips
- ㅅ (s) – the shape of a tooth
- ㅇ (silent) – the shape of the throat
It is a good story, and it is true. But there is one thing the textbooks never ask you to do: actually draw it.
2. Try drawing it
The story comes from the Hunminjeongeum Haerye, the 1446 manual that explains the new alphabet. Here are the two lines about the tongue, word for word:
牙取舌根閉喉形 — The molar sound (ㄱ) takes the shape of the tongue root closing the throat.
舌迺象舌附上腭 — The tongue sound (ㄴ) takes the shape of the tongue touching the upper gum.
Now take a side view of a head, the kind you see in any phonetics book: nose on the right, throat at the bottom. Trace the tongue while you say g. The root rises and bends back toward the throat. Trace it while you say n. The tip lifts and touches the gum behind the upper teeth.
Look at what you drew. The strokes are there, but they bend the wrong way. The letters come out upside down.
3. Now flip the head
같은 그림, 같은 글자 — 방향만 뒤집었다.
Turn the page upside down, so the throat is at the top and the lips are at the bottom. Now everything clicks into place.
- For g, the back of the tongue rises while the front of the tongue lies in the space behind the lower teeth. The bent tongue is exactly ㄱ.
- For n, the tip of the tongue touches the alveolar ridge behind the upper teeth. That shape is exactly ㄴ.
- The front tooth is ㅅ, the round throat is ㅇ, and the flat tense tongue with an open space above it is ㆆ – the lost letter for the glottal stop.
It is not only ㄱ and ㄴ. Two more letters make sense only when the head is upside down.
- ㅂ is built from ㅁ by adding strokes. If Sejong had only wanted to add a stroke, as he did for ㄴ → ㄷ, ㅂ would simply be ㅁ with a bar on top. Instead it has two posts sticking up. When you say b, the strain sits at the lower canine teeth. In an upright head they are below the lips, so the posts would point down. In the upside-down head the lower canines are on top – exactly where the two posts of ㅂ stand.
- ㆆ is the glottal stop. Here the tongue lies flat and tense, leaving an open space above it, and no vowel is made in that space. Draw the outline of that space and you get ㆆ upside down. Flip the head, and it is ㆆ the right way up.
One orientation, four letters. Many books draw the head facing left, and in that picture ㄱ can be made to look right. But turning a face left or right only swaps left and right; it cannot fix up and down. No upright head, facing either way, makes ㄱ, ㄴ, ㅂ and ㆆ fit at the same time. Make one assumption – the head is upside down – and all four fit at once. That is the whole argument of this post.
So the question is not whether the letters are pictures of the mouth. They are. The question is which way up the mouth was drawn. Draw it the way a fifteenth-century Korean king saw the world – with south, where the sun is, at the top – and the letters fit, one after another.
4. Why would Sejong flip it?
도성도(都城圖), 1700년대 후반의 서울 지도 — 남쪽이 위다. (국가유산청, 보물 제1560호)
This is a map of Seoul, drawn about three hundred years after Hangul. Look closely: the mountains at the bottom are the ones north of the city. The map is upside down by our standards. South is at the top.
That was not a mistake. A Korean king sat on his throne facing south, toward the sun, and ruled the land in front of him. The classic Book of Changes puts it in one line: “The sage faces south and listens to all under heaven.” So his maps were drawn the way he saw them – south, the bright side, on top.
The anatomy drawing at the top of this post follows the same convention. South, where the sun is, sits at the top of the picture – and in that orientation, ㄱ and ㄴ are simply what the tongue looks like.
5. Five places, one rule
조음 위치별로 육팔면체 전개도에 놓은 자음들 — 세 개의 거꾸로 된 머리 그림은 산스크리트 발음 안내서에서 가져왔다.
Here is the test. The three yellow heads were not drawn for Hangul at all. They come from a guide to Sanskrit pronunciation, and they show how the tongue moves for the velar, dental and palatal consonants of Sanskrit – a language whose alphabet was sorted by place in the mouth long before Sejong. The tongue shapes are left exactly as they were drawn. Only the heads are turned upside down, and each one then draws a Hangul letter by itself.
- Velar – the back of the tongue rises to the soft palate, while the front of the tongue (the blade) lies in the space behind the lower teeth: ㄱ → ㅋ
- Dental – the tip of the tongue touches the alveolar ridge, just behind the upper teeth: ㄴ → ㄷ → ㅌ
- Palatal – the blade of the tongue behind the front teeth: ㅅ → ㅈ → ㅊ (and ㅿ, the lost letter for a soft z)
- Labial – the lips, at the center of the net: ㅁ → ㅂ → ㅍ
- Glottal – the throat: ㅇ → ㆆ → ㅎ
Look closely at the palatal row, because the letters even show how the air moves. ㅅ (s) is a fricative: the air hisses out through a narrow gap that never closes, and the top of ㅅ is left open. ㅈ and ㅊ are affricates: the air is first stopped, then let out with the same hiss. Both letters are ㅅ with a bar across the top – and that bar is the stop. Stop plus hiss makes an affricate, and the shape of the letter already says so.
Five places in the mouth, one basic shape for each, and an extra stroke every time the sound gets stronger. That is the whole consonant system – and with the head upside down, every basic shape fits the part of the mouth it came from.
Fold the net into a solid and one more face appears, on the side opposite ㅂㅍ. This is where the soft sounds live.
입체의 부드러운 쪽 — 가운데 ㅁ, 둘레의 공명음들, 모서리를 흐르는 ㄹ.
At its center sits ㅁ, and around it are the sonorants – sounds you can hum or hold: ㄴ (n), ㆁ (ng), ㅿ (a z-like sound at the start of a syllable, a weak r at the end) and ㅇ. ㄹ (l/r) has no face of its own. It is a liquid(流音), and in this picture it does what its name says: it flows along the edges of the solid. Fittingly, ㄹ also pairs with more final consonants than any other letter – ㄺ ㄻ ㄼ ㄽ ㄾ ㄿ ㅀ.
Here is the whole thing as a solid you can hold. The consonant squares are painted in the five traditional colors: green for wood (ㄱㅋ), red for fire (ㄷㅌ), yellow for earth (ㅂㅍ), white for metal (ㅈㅊ) and black for water (ㆆㅎ). The voiced sounds are pale: the sonorants ㅁ ㅇ ㅿ ㄴ ㆁ in pink, the vowels ㅡ ㅣ ㆍ in yellow. The faces are see-through, so you can look inside. Think of the solid as a magnet: ㅂㅍ is the positive pole (+ 陽) and ㅁ, on the opposite side, is the negative pole (− 陰). Then watch ㄹ: it runs along two edges of the ㅁ square, crosses one edge of the ㆁ triangle, and finishes with two edges of the next square – drawing its own shape on the solid. Drag to turn it, or press Unfold to lay it flat again.
6. The lips
ㅁ·ㅂ·ㅍ — 편안한 입술, 긴장한 입술, 바람을 내보내는 입술.
The lips follow the same rule of one shape plus extra strokes – and, as we saw with ㅂ, even they are drawn from the upside-down head.
- ㅁ (m): the lips remain relaxed and soft, without tension.
- ㅂ (b/p): tension builds in the lower lip near the canine teeth – the two little posts of ㅂ.
- ㅍ (ph): muscular force is applied to both corners of the lips, and the air blows through.
Say ma, ba, pa in a mirror and watch your own lips tighten in that order.
7. Read more
This post is a short English version of ideas from the book 《正音으로 듣고쓰다》 (Listening and Writing with Jeongeum). The Korean originals go much deeper:
- 훈민정음 해례본 제자해 – 초성 17자의 제자 원리 – how the 17 consonants were designed (Korean)
- ㆁ ㅿ ㆆ ㆍ의 음가 – the four lost letters and the sounds they made (Korean)
- IPA자음 vs 正音자음 – the 28 letters laid on the IPA consonant chart (Korean)