Week 2
Vowels: 10 Sounds Built from Sky, Earth & Human
Cheonjiin (天地人) — Three Shapes That Design Every Vowel
WEEK 2
Vowels: 10 Sounds Built from Sky, Earth & Human
Quick Review from Last Week
Hangul assembles consonants and vowels inside square blocks.
Initial consonant + Middle vowel + Final consonant (optional)
↓ ↓ ↓
[ ㄱ ] + [ ㅏ ] = 가
Today we're learning the 10 simple vowels that fill the middle slot — the nucleus of that block.
Why a Syllable Can't Exist Without a Vowel
In linguistics, every syllable is built around a nucleus. In Korean, that nucleus is always a vowel.
Consonants create the start or end of a sound, but on their own they can't sustain a continuous flow of air. Vowels are sounds where the mouth is open and air moves freely — the vocal cords vibrate, nothing is blocked. That's why vowels are what let a sound last long enough to form a syllable.
ㄱ alone → Tries to make [k], immediately hits a wall. No syllable.
ㄱ + ㅏ → Block (ㄱ) + Open (ㅏ) = 가 [ga] Syllable complete.
Same deal in English. "str-" isn't a syllable on its own. It needs a vowel, like in "street," to become a word. Hangul bakes this rule right into its letter structure — leave the middle slot empty and the character simply doesn't exist.
Three Shapes That Make Every Vowel
When King Sejong designed the vowels, he started from three elements:
ㆍ (Sky 天) — a round dot
ㅡ (Earth 地) — a flat horizontal line
ㅣ (Human 人) — a straight vertical line
This is the Cheonjiin (天地人) principle — Heaven, Earth, and Humanity.
ㆍ (Arae-a) — The Lost Sound
ㆍ was an independent vowel in 15th-century Hunminjeongeum. Its original sound was likely a back mid vowel — estimated to be a bit more open than the modern ㅓ [ʌ]. Back then it was a completely distinct phoneme, separate from both ㅏ and ㅓ.
Over the 16th–18th centuries, this sound gradually merged into ㅏ or ㅓ, and was eventually retired from Modern Standard Korean.
Fascinatingly, it's still alive in the Jeju dialect. Jeju Korean is the only surviving Korean dialect that preserves the original sound value of ㆍ, making it a linguistically precious resource.
In modern Hangul, ㆍ lives on in disguise — absorbed as the "dot" component in vowels like ㅏ, ㅓ, ㅗ, and ㅜ.
The 6 Basic Vowels: Cheonjiin Combinations
ㅏ = ㅣ + dot (right side) → Sky to the right of Human [a]
ㅓ = ㅣ + dot (left side) → Sky to the left of Human [ʌ]
ㅗ = ㅡ + dot (above) → Sky above Earth [o]
ㅜ = ㅡ + dot (below) → Sky below Earth [u]
ㅡ = Earth itself [ɯ]
ㅣ = Human itself [i]
Just three shapes. Six vowels. That's Sejong's design.
✏️ Activity 1: Cracking the Cheonjiin Code
Look at the combination rules below and fill in the blanks with the vowel that gets created.
ㅣ + dot (right side) → ___ [a]
ㅣ + dot (left side) → ___ [ʌ]
ㅡ + dot (above) → ___ [o]
ㅡ + dot (below) → ___ [u]
Earth's shape as-is → ___ [ɯ]
Human's shape as-is → ___ [i]
Now place the 6 completed vowels in the correct spots on this vowel chart:
Front Back
Unrounded Unrounded Rounded
────── ────── ──────
High ___ ___ ___
Mid ___ ___
Low ___
What Makes Vowels Different: Tongue, Lips & Jaw
Three features separate one vowel from another.
① Tongue front-to-back position
Front — tongue toward the front of the mouth e.g. ㅣ [i], ㅔ [e], ㅐ [ɛ]
Back — tongue toward the back of the mouth e.g. ㅡ [ɯ], ㅏ [a], ㅜ [u]
② Tongue height
High — tongue rises up e.g. ㅣ [i], ㅡ [ɯ], ㅜ [u]
Mid — tongue in the middle e.g. ㅔ [e], ㅓ [ʌ], ㅗ [o]
Low — tongue drops down e.g. ㅐ [ɛ], ㅏ [a]
③ Lip shape
Unrounded — lips spread flat or neutral e.g. ㅣ [i], ㅡ [ɯ], ㅓ [ʌ], ㅏ [a]
Rounded — lips pushed forward/puckered e.g. ㅜ [u], ㅗ [o], ㅚ [ø], ㅟ [y]
The Vowel Chart — All 10 Simple Vowels
Front Back
Unrounded Rounded Unrounded Rounded
────── ────── ────── ──────
High ㅣ[i] ㅟ[y] ㅡ[ɯ] ㅜ[u]
Mid ㅔ[e] ㅚ[ø] ㅓ[ʌ] ㅗ[o]
Low ㅐ[ɛ] ㅏ[a]
How to read this chart:
- Further left = tongue further forward in the mouth
- Higher up = tongue higher in the mouth
- Right-hand columns (Rounded) = lips are puckered for those sounds
The 10 Simple Vowels: How Were They Made?
Add ㅣ to each of the 6 basics and you get 4 more:
ㅏ + ㅣ → ㅐ [ɛ] (open a bit wider than ㅔ)
ㅓ + ㅣ → ㅔ [e] (mouth half-open)
ㅗ + ㅣ → ㅚ [ø] (say "ee" with rounded lips)
ㅜ + ㅣ → ㅟ [y] (say "ee" with lips pushed forward)
6 basics + 4 ㅣ-blends = 10 simple vowels. Done.
The Real-World Pronunciation Situation in Modern Korean
| Vowel | Original sound | Modern reality |
|---|---|---|
| ㅐ [ɛ] | Front low vowel, mouth more open than ㅔ | Most speakers don't distinguish it from ㅔ |
| ㅔ [e] | Front mid vowel, tongue further forward than ㅓ | Most speakers don't distinguish it from ㅐ |
| ㅚ [ø] | Rounded front mid vowel (simple vowel) | Most speakers use [we] instead (diphthong) |
| ㅟ [y] | Rounded front high vowel (simple vowel) | Most speakers use [wi] instead (diphthong) |
In other words: even native Korean speakers often "get these wrong." Technically they're distinct simple vowels in Standard Korean, but the real-world pronunciations in the table above sound perfectly natural in everyday conversation. For learners, it's totally reasonable to learn the everyday versions first and fine-tune toward the standard later.
(The y-series diphthongs ㅑ ㅕ ㅛ ㅠ and compound diphthongs ㅘ ㅙ ㅝ ㅞ ㅢ are covered in Week 6.)
Full Reference Table: All 10 Simple Vowels
| Vowel | Romanization | IPA | Tongue position | Tongue height | Lips | Pronunciation guide |
|---|---|---|---|---|---|---|
| ㅣ | i | [i] | Front | High | Unrounded | Pull corners of mouth wide, say "ee" |
| ㅔ | e | [e] | Front | Mid | Unrounded | "eh" — mouth half-open, sound from the front |
| ㅐ | ae | [ɛ] | Front | Low | Unrounded | "ae" — open your mouth a touch wider than ㅔ |
| ㅡ | eu | [ɯ] | Back | High | Unrounded | Pull lips sideways and say "eu" — no equivalent in English |
| ㅓ | eo | [ʌ] | Back | Mid | Unrounded | "eo" — similar to the u in English "bus" |
| ㅏ | a | [a] | Back | Low | Unrounded | Open wide and say "ah" |
| ㅜ | u | [u] | Back | High | Rounded | Push lips forward and say "oo" |
| ㅗ | o | [o] | Back | Mid | Rounded | Round your lips and say "oh" |
| ㅟ | wi | [y→wi] | Front | High | Rounded | Standard [y], everyday [wi] |
| ㅚ | oe | [ø→we] | Front | Mid | Rounded | Standard [ø], everyday [we] |
✏️ Activity 2: Classify Vowels on the Chart
Fill in the table using the three criteria from the vowel chart (tongue position / tongue height / lip shape).
┌───────┬────────────────┬──────────────┬────────────────┐
│ Vowel │ Tongue position │ Tongue height │ Lip shape │
├───────┼────────────────┼──────────────┼────────────────┤
│ ㅣ │ │ │ │
│ ㅏ │ │ │ │
│ ㅜ │ │ │ │
│ ㅔ │ │ │ │
│ ㅡ │ │ │ │
│ ㅗ │ │ │ │
└───────┴────────────────┴──────────────┴────────────────┘
(Hint: Tongue position = Front/Back, Tongue height = High/Mid/Low, Lips = Unrounded/Rounded)
Placement Rules: Where Does a Vowel Go?
A vowel's shape determines where it sits inside the syllable block.
[Vertical vowels] — attach to the RIGHT of the consonant
ㅏ ㅐ ㅓ ㅔ ㅣ
e.g. ㄴ + ㅏ → 나 ┌──┬─┐
│ㄴ│ㅏ│
└──┴─┘
[Horizontal vowels] — attach BELOW the consonant
ㅗ ㅚ ㅜ ㅟ ㅡ
e.g. ㄴ + ㅗ → 노 ┌────┐
│ ㄴ │
├────┤
│ ㅗ │
└────┘
✏️ Activity 3: Vertical or Horizontal?
Classify each vowel below as vertical or horizontal, then write out the syllable you get when you combine it with ㅁ.
┌───────┬───────────────┬──────────────────────┬──────────────┐
│ Vowel │ Vertical/Horiz │ ㅁ + vowel = ? │ Romanization │
├───────┼───────────────┼──────────────────────┼──────────────┤
│ ㅏ │ │ ___ │ [ma] │
│ ㅗ │ │ ___ │ [mo] │
│ ㅣ │ │ ___ │ [mi] │
│ ㅜ │ │ ___ │ [mu] │
│ ㅓ │ │ ___ │ [meo] │
│ ㅡ │ │ ___ │ [meu] │
└───────┴───────────────┴──────────────────────┴──────────────┘
Syllables That Start with a Vowel: The Role of ㅇ
Vowels always need a consonant to sit next to. But what about sounds like "아", "오", "우" that begin with a vowel and nothing else?
The answer is ㅇ.
When the initial consonant slot is empty → insert ㅇ as a silent placeholder.
ㅇ in the initial position makes no sound at all.
아 = ㅇ (silent) + ㅏ → [a]
오 = ㅇ (silent) + ㅗ → [o]
우 = ㅇ (silent) + ㅜ → [u]
이 = ㅇ (silent) + ㅣ → [i]
(ㅇ in the final consonant position makes a completely different sound — covered in Week 5.)
✏️ Activity 4: Fill in the ㅇ Placeholder
Write these sounds in Hangul. Don't forget the ㅇ in the initial slot!
[a] → ___ (hint: ㅇ + ㅏ)
[o] → ___ (hint: ㅇ + ㅗ)
[e] → ___ (hint: ㅇ + ㅔ)
[i] → ___ (hint: ㅇ + ㅣ)
[ɯ] → ___ (hint: ㅇ + ㅡ)
Pronunciation Guide: Two Sounds That Trip Up English Speakers
Eight of the ten vowels have a fairly intuitive English equivalent. But two of them are genuinely tricky.
ㅓ [ʌ] — Close to English, But Not Quite
Nearest English sounds: the u in "bus", the u in "fun", the u in "cut"
The difference: your mouth opens a bit more than for the English [ʌ].
Watch out: don't read it as two syllables "eo." It's one syllable.
Practice words: 버스 [beo.seu] 어머니 [eo.meo.ni]
ㅐ [ɛ] vs ㅔ [e] — You Should Know the Difference, But Real Life Is Messier
ㅔ [e]: tongue front, mid height. "eh" — mouth half-open.
ㅐ [ɛ]: tongue front, lower. "ae" — open your mouth a touch more than ㅔ.
Minimal pair practice:
세다 [se.da] (to be strong) vs 새다 [sɛ.da] (to leak)
베다 [be.da] (to cut) vs 배다 [bɛ.da] (to soak in)
In Standard Korean these are two distinct sounds. In practice, the vast majority of modern Korean speakers merge them both into [e]. For learners, treating them as the same sound first — then distinguishing them by spelling later in context — is a perfectly reasonable approach.
ㅡ [ɯ] — A Sound English Doesn't Have
There's no English equivalent. Seriously, none.
How to do it: Spread the corners of your mouth sideways
(as if you're about to say ㅣ),
then barely open your mouth and hum a low "eu..."
Practice words: 그림 [geu.rim] 크다 [keu.da] 스트레스 [seu.teu.re.seu]
✏️ Activity 5: Vowel Hunting in Loanwords
These are K-pop, food, and everyday loanwords you already know. Find and write the vowel in each syllable.
① 소파 — sofa [so.pa]
Vowel in 소: ___ Vowel in 파: ___
② 피자 — pizza [pi.ja]
Vowel in 피: ___ Vowel in 자: ___
③ 버스 — bus [beo.seu]
Vowel in 버: ___ Vowel in 스: ___
④ 커피 — coffee [keo.pi]
Vowel in 커: ___ Vowel in 피: ___
⑤ 아이돌 — idol [a.i.dol]
Vowel in 아: ___ Vowel in 이: ___
(Hint: the vowel is the part of the character made of straight lines and dots.)
Today's Writing Practice: Drawing with Cheonjiin
We'll start with the basic Cheonjiin shapes and work up to the combined vowels, in order.
Step 1: Two Basic Shapes
ㅡ (Earth) — 1 stroke
① → Horizontal stroke: draw a flat line from left to right
Result: ─
ㅣ (Human) — 1 stroke
① ↓ Vertical stroke: draw straight down from top to bottom
Result: │
Step 2: Combine to Complete a Vowel
ㅏ [a] — ㅣ + short horizontal branch (right)
① ↓ Vertical stroke (ㅣ)
② → From the middle of ①, branch out to the right with a short stroke
Cheonjiin: Sky (ㆍ) to the right of Human (ㅣ) → ㅏ
Result: a vertical line with a short branch out the right side
ㅗ [o] — ㅡ + short vertical branch (up)
① — Horizontal stroke (ㅡ)
② ↑ From the middle of ①, branch up with a short stroke
Cheonjiin: Sky (ㆍ) above Earth (ㅡ) → ㅗ
Result: a horizontal line with a short vertical branch up from the center
┌─────────────────────────────────────────────────┐
│ │
│ │
│ │
│ │
├─────────────────────────────────────────────────┤
│ ✏️ Practice writing in this order: ㅡ → ㅣ → ㅏ → ㅗ │
│ Write each vowel 5 times, keeping the Cheonjiin │
│ principle in mind as you draw each stroke. │
└─────────────────────────────────────────────────┘
✏️ Activity 6: Complete the Word — Vowels Only
The initial consonants are already in place. Just add the vowels to finish each word.
① 나비 — nabi [na.bi] (butterfly)
나 = ㄴ + ___
비 = ㅂ + ___
② 고기 — gogi [go.gi] (meat)
고 = ㄱ + ___
기 = ㄱ + ___
③ 머리 — meori [meo.ri] (head)
머 = ㅁ + ___
리 = ㄹ + ___
④ 구두 — gudu [gu.du] (dress shoes)
구 = ㄱ + ___
두 = ㄷ + ___
⑤ 게임 — game [ke.im] (game)
게 = ㄱ + ___
임 = ㅇ + ___ + ㅁ
Mini Quiz: Week 2
Q1. In the Cheonjiin principle, what does ㅡ represent?
┌──────────────────────────────┐
│ A) Sky │
│ B) Earth │
│ C) Human │
│ D) Wind │
│ │
│ Answer: ____ │
└──────────────────────────────┘
Q2. What sound does ㅇ make in the initial consonant position?
┌──────────────────────────────┐
│ A) [n] │
│ B) [g] │
│ C) No sound (silent placeholder) │
│ D) [ng] │
│ │
│ Answer: ____ │
└──────────────────────────────┘
Q3. Which of these is NOT a vertical vowel?
┌──────────────────────────────┐
│ A) ㅏ │
│ B) ㅣ │
│ C) ㅗ │
│ D) ㅓ │
│ │
│ Answer: ____ │
└──────────────────────────────┘
Q4. What does your mouth do when pronouncing ㅡ?
┌──────────────────────────────┐
│ A) Lips push forward/pucker │
│ B) Corners of mouth pull sideways │
│ C) Open wide │
│ D) Open halfway │
│ │
│ Answer: ____ │
└──────────────────────────────┘
(Answers: Q1-B, Q2-C, Q3-C, Q4-B)
Activity Answer Key
Activity 1 — Cracking the Cheonjiin Code
ㅣ + dot (right side) → ㅏ [a]
ㅣ + dot (left side) → ㅓ [ʌ]
ㅡ + dot (above) → ㅗ [o]
ㅡ + dot (below) → ㅜ [u]
Earth's shape as-is → ㅡ [ɯ]
Human's shape as-is → ㅣ [i]
Vowel chart placement answers:
Front Back
Unrounded Unrounded Rounded
────── ────── ──────
High ㅣ ㅡ ㅜ
Mid ㅓ ㅗ
Low ㅏ
Activity 2 — Classify Vowels on the Chart
ㅣ Front High Unrounded
ㅏ Back Low Unrounded
ㅜ Back High Rounded
ㅔ Front Mid Unrounded
ㅡ Back High Unrounded
ㅗ Back Mid Rounded
Activity 3 — Vertical or Horizontal?
ㅏ Vertical → 마 [ma]
ㅗ Horizontal → 모 [mo]
ㅣ Vertical → 미 [mi]
ㅜ Horizontal → 무 [mu]
ㅓ Vertical → 머 [meo]
ㅡ Horizontal → 므 [meu]
Activity 4 — Fill in the ㅇ Placeholder
[a] → 아
[o] → 오
[e] → 에
[i] → 이
[ɯ] → 으
Activity 5 — Vowel Hunting in Loanwords
① 소파: 소(ㅗ) 파(ㅏ)
② 피자: 피(ㅣ) 자(ㅏ)
③ 버스: 버(ㅓ) 스(ㅡ)
④ 커피: 커(ㅓ) 피(ㅣ)
⑤ 아이돌: 아(ㅏ) 이(ㅣ)
Activity 6 — Complete the Word — Vowels Only
① 나비: 나(ㅏ) 비(ㅣ)
② 고기: 고(ㅗ) 기(ㅣ)
③ 머리: 머(ㅓ) 리(ㅣ)
④ 구두: 구(ㅜ) 두(ㅜ)
⑤ 게임: 게(ㅔ) 임(ㅣ)
What You Learned This Week
- No vowel = no syllable — the vowel is the nucleus at the heart of every syllable
- ㆍ (Arae-a) was an independent vowel in the 15th century, now extinct — survives only in the Jeju dialect
- Three basic shapes (ㆍ Sky, ㅡ Earth, ㅣ Human) design 6 core vowels — the Cheonjiin principle
- 6 basics + 4 ㅣ-blends (ㅐ ㅔ ㅚ ㅟ) = 10 simple vowels
- Vowels are classified by tongue front-to-back, tongue height, and lip shape — the vowel chart
- ㅚ and ㅟ are officially simple vowels but are actively becoming diphthongs in modern speech
- ㅐ and ㅔ are technically distinct but most modern speakers merge them
- Vertical vowels (ㅏ ㅐ ㅓ ㅔ ㅣ) go to the right of the consonant; horizontal vowels (ㅗ ㅚ ㅜ ㅟ ㅡ) go below
- Initial ㅇ is a silent placeholder — it holds the spot so the block can be complete
- You practiced the Cheonjiin stroke order: ㅡ → ㅣ → ㅏ → ㅗ
"Next week: Consonants — 14 letters drawn from the shape of the mouth itself."
🔗 kkultongkorea.com | 📧 kkultongkorea@gmail.com