WEEK 6

Act Two of Vowels: Add a Glide and Everything Changes

Last Week's Review

Here's what you've covered so far:

Week 1: Hangul block writing — initial consonant + vowel + final consonant
Week 2: 10 monophthongs (ㅏ ㅐ ㅓ ㅔ ㅗ ㅚ ㅜ ㅟ ㅡ ㅣ)
Week 3: 14 consonants (9 plain + 5 aspirated)
Week 4: 5 tense consonants — completing the plain / aspirated / tense trio
Week 5: 7 final consonant sounds, vowel linking, and double final consonants

Back in Week 2, you learned 10 monophthongs. But did you notice that ㅑ ㅕ ㅛ ㅠ were missing from that list?

And ㅚ and ㅟ definitely showed up in Week 2 — so why are they making a comeback today?

There's a reason. This week, we explain it.

Monophthongs vs. Diphthongs: What's the Difference?

The vowels you've learned so far — ㅏ ㅓ ㅗ ㅜ ㅡ ㅣ and the rest — are monophthongs.

A monophthong is a vowel where your mouth shape stays the same from start to finish.

ㅏ [a]:  mouth open wide → stays that way
ㅗ [o]:  lips rounded → stays that way

Diphthongs are different.

Diphthong:  your mouth shape shifts once while the sound plays
            starting position ─────────────────→ ending position

English has diphthongs too:

"say"  [seɪ]  — starts at [e], glides toward [ɪ]
"go"   [goʊ]  — starts at [o], glides toward [ʊ]
"my"   [maɪ]  — starts at [a], glides toward [ɪ]

Korean diphthongs work the same way — except they follow clear, predictable patterns.

Three Types of Diphthongs

Korean diphthongs fall into three main groups:

1. y-series  — glide [j] + monophthong
               ㅑ[ja]  ㅕ[jʌ]  ㅛ[jo]  ㅠ[ju]

2. w-series  — glide [w] + monophthong
               ㅘ[wa]  ㅙ[wɛ]  ㅝ[wʌ]  ㅞ[we]

3. Monophthongs that became diphthongs — officially monophthongs, but most
               modern speakers pronounce them as diphthongs
               ㅚ[we]  ㅟ[wi]

4. One-of-a-kind diphthong
               ㅢ[ɯi]

A glide is a short, sliding sound that lives somewhere between a consonant and a vowel. [j] is the first sound in the English word "yes," and [w] is the first sound in "water."

Full Diphthong Reference Chart

Before diving into the details, get the big picture first.

┌──────────────────────────┬────────────────────────────────────────┐
│ Type                      │ Vowels                                 │
├──────────────────────────┼────────────────────────────────────────┤
│ y-series [j + vowel]      │ ㅑ[ja]   ㅕ[jʌ]   ㅛ[jo]   ㅠ[ju]   │
├──────────────────────────┼────────────────────────────────────────┤
│ w-series [w + vowel]      │ ㅘ[wa]   ㅙ[wɛ]   ㅝ[wʌ]   ㅞ[we]   │
├──────────────────────────┼────────────────────────────────────────┤
│ Monophthong → Diphthong   │ ㅚ[we]   ㅟ[wi]                       │
│ (by modern pronunciation) │                                        │
├──────────────────────────┼────────────────────────────────────────┤
│ One-of-a-kind diphthong   │ ㅢ[ɯi]                                 │
└──────────────────────────┴────────────────────────────────────────┘

Let's take each type one at a time.

Part 1. The y-Series Diphthongs [j + vowel]

The y-series has a simple rule.

Take a monophthong you already know, and add a [j] sound in front.

ㅏ [a]  →  ㅑ [ja]  ("y" + "ah")
ㅓ [ʌ]  →  ㅕ [jʌ]  ("y" + "uh")
ㅗ [o]  →  ㅛ [jo]  ("y" + "oh")
ㅜ [u]  →  ㅠ [ju]  ("y" + "oo")

The shapes follow a pattern too. Just add one more stroke to the base monophthong:

Vertical vowels:
  ㅏ (1 horizontal tick) → ㅑ (2 horizontal ticks)
  ㅓ (1 horizontal tick) → ㅕ (2 horizontal ticks)

Horizontal vowels:
  ㅗ (1 vertical tick) → ㅛ (2 vertical ticks)
  ㅜ (1 vertical tick) → ㅠ (2 vertical ticks)

This is an extension of the Heaven-Earth-Human design principle — one dot (ㆍ) means monophthong; two dots mean y-series.

y-Series Vowel Chart

Vowel	IPA	English hint
ㅑ	[ja]	"ya!" (야!)
ㅕ	[jʌ]	"yuh" (short)
ㅛ	[jo]	"yo!"
ㅠ	[ju]	"you"

Example Words — y-Series

야 [ja]    — 야구  [ja.gu]         (baseball)     ㅇ(silent) + ㅑ
여 [jʌ]    — 여기  [jʌ.gi]         (here)         ㅇ(silent) + ㅕ
요 [jo]    — 요리  [jo.ɾi]         (cooking)      ㅇ(silent) + ㅛ
유 [ju]    — 유리  [ju.ɾi]         (glass)        ㅇ(silent) + ㅠ

With a real initial consonant:

묘 [mjo]   — 묘하다  [mjo.ha.da]   (mysterious)   ㅁ + ㅛ
겨 [kjʌ]   — 겨울   [kjʌ.ul]       (winter)       ㄱ + ㅕ
교 [kjo]   — 교실   [kjo.sil]      (classroom)    ㄱ + ㅛ
규 [kju]   — 규칙   [kju.tɕʰik̚]   (rule)         ㄱ + ㅠ

✏️ Activity 1: Monophthong → y-Series Conversion

Write the matching y-series vowel in each blank, then read the example word aloud.

Monophthong  →  y-series   Reading example
─────────────────────────────────
ㅏ [a]   →   ___     야구 (baseball)
ㅓ [ʌ]   →   ___     여기 (here)
ㅗ [o]   →   ___     요리 (cooking)
ㅜ [u]   →   ___     유리 (glass)

Part 2. The w-Series Diphthongs [w + vowel]

The w-series is formed when ㅗ or ㅜ combines with another vowel.

The [w] sound comes naturally from the lip-rounding you already do for ㅗ[o] and ㅜ[u].

ㅗ[o] + ㅏ[a]  →  ㅘ  [wa]   "wah"
ㅗ[o] + ㅐ[ɛ]  →  ㅙ  [wɛ]   "weh"
ㅜ[u] + ㅓ[ʌ]  →  ㅝ  [wʌ]   "wuh"
ㅜ[u] + ㅔ[e]  →  ㅞ  [we]   "weh"

Look at the shapes and the logic reveals itself:

ㅘ  =  ㅗ + ㅏ  (horizontal stroke below + vertical stroke on right)
ㅙ  =  ㅗ + ㅐ  (horizontal stroke below + two vertical strokes)
ㅝ  =  ㅜ + ㅓ  (horizontal stroke above + vertical stroke on left)
ㅞ  =  ㅜ + ㅔ  (horizontal stroke above + two vertical strokes)

w-Series Vowel Chart

Vowel	Components	IPA	English hint
ㅘ	ㅗ[o]+ㅏ[a]	[wa]	"wah!"
ㅙ	ㅗ[o]+ㅐ[ɛ]	[wɛ]	"weh"
ㅝ	ㅜ[u]+ㅓ[ʌ]	[wʌ]	"wuh"
ㅞ	ㅜ[u]+ㅔ[e]	[we]	"weh"

Modern Pronunciation Note: ㅙ and ㅞ

Standard pronunciation distinguishes ㅙ[wɛ] from ㅞ[we]. However, the vast majority of modern Korean speakers pronounce both vowels identically as [we].

Standard:  ㅙ [wɛ] ≠ ㅞ [we]
Modern:    ㅙ [we] = ㅞ [we]  (virtually no distinction)

You'll need to tell the two apart when reading and listening, but when speaking, one [we] covers both.

Example Words — w-Series

봐  [pwa]   — 봐요  [pwa.jo]      (please look)    ㅂ + ㅘ
왜  [wɛ]    — 왜요? [wɛ.jo]       (why?)           ㅇ + ㅙ
워  [wʌ]    — 워크숍 [wʌ.kʰɯ.sop̚] (workshop)      ㅇ + ㅝ
웨  [we]    — 웨이터 [we.i.tʰʌ]   (waiter)         ㅇ + ㅞ

✏️ Activity 2: Spot the w-Series Vowel

Read each word aloud, then write the w-series vowel you find in each one.

과자  [kwa.dʑa]   (snack)    →  w-series vowel: ___
돼지  [twɛ.dʑi]   (pig)      →  w-series vowel: ___
줘    [tɕwʌ]      (give me)  →  w-series vowel: ___
웨딩  [we.diŋ]    (wedding)  →  w-series vowel: ___

Part 3. Monophthongs That Became Diphthongs — ㅚ and ㅟ

Now those two vowels from Week 2 make their return.

In Week 2, ㅚ and ㅟ were on the monophthong list. So why are they showing up in the diphthong unit?

Standard pronunciation:  ㅚ and ㅟ are monophthongs
                          ㅚ [ø]  (rounded lips + front tongue position)
                          ㅟ [y]  (rounded lips + high tongue position)

Modern pronunciation:    Most Korean speakers produce them as diphthongs
                          ㅚ → [we]  (same as ㅞ)
                          ㅟ → [wi]

The practical takeaway: If your goal is to communicate in modern Korean, pronouncing ㅚ and ㅟ as diphthongs will sound completely natural.

ㅚ  →  pronounced [we]     e.g. 외국인 [we.gu.gin]  (foreigner)
ㅟ  →  pronounced [wi]     e.g. 귀 [kwi]            (ear)

Vowel	Standard IPA	Modern pronunciation	English hint
ㅚ	[ø]	[we]	"weh"
ㅟ	[y]	[wi]	"we"

Example Words — ㅚ ㅟ

외  [we]  — 외국  [we.guk̚]    (foreign country)   ㅇ + ㅚ
위  [wi]  — 위쪽  [wi.t͈ok̚]   (upward / above)    ㅇ + ㅟ
쉬  [ɕwi] — 쉬다  [ɕwi.da]    (to rest)            ㅅ + ㅟ

✏️ Activity 3: Choose the Modern Pronunciation of ㅚ and ㅟ

For each underlined vowel, choose the correct modern pronunciation.

① 외국인  (foreigner)
   Modern pronunciation of ㅚ:   (A) [ø]    (B) [we]    (C) [wi]
   Answer: ___

② 귀여워  (cute)
   Modern pronunciation of ㅟ:   (A) [y]    (B) [we]    (C) [wi]
   Answer: ___

③ Which statement best describes the modern pronunciations of 왜 (why) and 외 (foreign)?
   (A) They're different — 왜 is [wɛ] and 외 is [wɛ] but distinct
   (B) They're the same — both pronounced [we]
   (C) 왜 is [we] and 외 is [ø]
   Answer: ___

Part 4. The One-of-a-Kind Diphthong: ㅢ

ㅢ is the most unique diphthong in Korean.

ㅢ = ㅡ[ɯ] + ㅣ[i]  →  [ɯi]

How to pronounce it:
  1. Start at the ㅡ[ɯ] position (tongue pushed back, lips flat)
  2. Glide toward ㅣ[i] (tongue moves forward)

ㅢ belongs to neither the y-series nor the w-series. It's a uniquely Korean diphthong — a ㅡ→ㅣ glide with no [j] or [w] involved.

Three Ways ㅢ Is Pronounced

Same letter, different sound depending on position:

① First syllable     →  [ɯi]   의사 [ɯi.sa]   (doctor)
② Middle syllable    →  [i]    회의 [hwe.i]   (meeting)
③ Particle '의'      →  [e]    나의 [na.e]    (my / of me)

Why does it change?

ㅢ[ɯi] is a complex sound that requires your tongue to travel from ㅡ all the way to ㅣ. When it appears mid-word, the surrounding syllables put enough pressure on it that it simplifies down to [i]. When it's used as a possessive particle, fast natural speech trims it further to [e]. The rules look complicated, but once you know the position, the pattern clicks.

💡 Even native Koreans find this tricky. Most native speakers can't explain the rule explicitly — they just do it on autopilot. It's totally fine if this feels strange at first. Read through it a few times and it'll start to feel natural.

Example Words — ㅢ

의사 [ɯi.sa]  — 의사  (doctor)         first syllable → [ɯi]
의미 [ɯi.mi]  — 의미  (meaning)        first syllable → [ɯi]
나의 [na.e]   — 나의  (my)             particle → [e]

✏️ Activity 4: Applying the ㅢ Pronunciation Rules

Choose the correct pronunciation — [ɯi], [i], or [e] — for the underlined 의 in each word.

① <의>자  (chair — first syllable)           →  pronunciation: [   ]
② 주<의>  (attention — middle syllable)      →  pronunciation: [   ]
③ 희<의>  (hope — possessive particle '의')  →  pronunciation: [   ]
④ <의>원  (hospital — first syllable)        →  pronunciation: [   ]

Today's Writing Practice

Diphthongs look complex, but when you break them down, they're just combinations of vowels you already know.

ㅑ [ja] — y-series

  Start with ㅏ and add one extra horizontal tick.

  ㅏ:  ① ↓ vertical stroke  ② → horizontal tick (from center, going right)
  ㅑ:  ① ↓ vertical stroke  ② → horizontal tick (upper, going right)
                             ③ → horizontal tick (center, going right)

  야 [ja]:

  ┌───┬──┐
  │ ㅇ │ㅑ│  →  야 [ja]
  └───┴──┘

ㅛ [jo] — y-series

  Start with ㅗ and add one extra vertical tick.

  ㅗ:  ① → horizontal stroke  ② ↑ vertical tick (center, 1 tick)
  ㅛ:  ① → horizontal stroke  ② ↑ vertical tick (left side, going up)
                               ③ ↑ vertical tick (right side, going up)

  요 [jo]:

  ┌─────┐
  │  ㅇ  │
  ├─────┤
  │  ㅛ  │  →  요 [jo]
  └─────┘

ㅘ [wa] — w-series

  Write ㅗ and ㅏ side by side.
  Because ㅗ is a horizontal vowel, the whole vowel block sits below the initial consonant.

  봐 [pwa]:

  ┌───┬───┐
  │   ㅂ   │      ← initial consonant: fills the top cell
  ├───┼───┤
  │ ㅗ │ ㅏ │      ← vowel: ㅗ (left) + ㅏ (right)
  └───┴───┘

ㅝ [wʌ] — w-series

  Combine ㅜ and ㅓ.

  뭐 [mwʌ]:

  ┌───┬───┐
  │   ㅁ   │
  ├───┼───┤
  │ ㅜ │ ㅓ │      ← ㅜ (left) + ㅓ (right)
  └───┴───┘

ㅢ [ɯi] — one-of-a-kind diphthong

  Combine ㅡ (horizontal) and ㅣ (vertical).
  ㅡ sits below the initial consonant; ㅣ attaches to the right.

  의 [ɯi]:

  ┌───┬───┐
  │ ㅇ │   │   ← initial consonant ㅇ (upper left)
  ├───┼───┤
  │ ㅡ │ ㅣ│   ← ㅡ (left) + ㅣ (right) = ㅢ
  └───┴───┘

┌─────────────────────────────────────────────────────────┐
│                                                         │
│                                                         │
│                                                         │
├─────────────────────────────────────────────────────────┤
│  ✏️ Write each of these twice: 야 · 요 · 봐 · 뭐 · 의  │
│  Pay attention to vowel position (vertical/horizontal/  │
│  compound).                                             │
└─────────────────────────────────────────────────────────┘

Word writing:

┌─────────────────────────────────────────────────────────┐
│                                                         │
│  Write each of these once: 야구 · 여기 · 봐요 · 의사   │
│                                                         │
└─────────────────────────────────────────────────────────┘

✏️ Activity 5: Diphthong Sorting Challenge

Sort the vowels below into the correct category. (Try it without looking at the reference chart!)

Vowel list: ㅠ ㅙ ㅢ ㅑ ㅝ ㅚ ㅕ ㅞ ㅟ ㅛ ㅘ

┌──────────────────────────┬────────────────────────────┐
│ Type                      │ Vowels                     │
├──────────────────────────┼────────────────────────────┤
│ y-series                  │                            │
├──────────────────────────┼────────────────────────────┤
│ w-series                  │                            │
├──────────────────────────┼────────────────────────────┤
│ Monophthong → Diphthong   │                            │
│ (ㅚ ㅟ)                   │                            │
├──────────────────────────┼────────────────────────────┤
│ One-of-a-kind (ㅢ)        │                            │
└──────────────────────────┴────────────────────────────┘

Real Words with Diphthongs

Words you'll actually run into in K-pop and K-dramas:

야구  [ja.gu]        baseball       — contains ㅑ
여기  [jʌ.gi]        here           — contains ㅕ
교실  [kjo.sil]      classroom      — contains ㅛ
유리  [ju.ɾi]        glass          — contains ㅠ

봐요  [pwa.jo]       please look    — contains ㅘ
왜요  [wɛ.jo]        why?           — contains ㅙ
뭐야  [mwʌ.ja]       what is it?    — contains ㅝ

외국  [we.guk̚]      foreign        — contains ㅚ
위    [wi]           above / top    — contains ㅟ
의사  [ɯi.sa]        doctor         — contains ㅢ

✏️ Activity 6: Reading Vowels in Context

Read each word aloud. Then mark whether the underlined vowel is a monophthong or diphthong.

Word            Reading          Monophthong / Diphthong
────────────────────────────────────────────────────────
① 야구  [ja.gu]    (baseball)    ㅑ: ________  ㅜ: ________
② 외국  [we.guk̚]  (foreign)    ㅚ: ________
③ 의사  [ɯi.sa]   (doctor)     ㅢ: ________  ㅏ: ________
④ 유리  [ju.ɾi]   (glass)      ㅠ: ________  ㅣ: ________
⑤ 봐요  [pwa.jo]  (please look) ㅘ: ________  ㅛ: ________

After reading: which word was the trickiest to pronounce?

Mini Quiz: Week 6

Q1. Which word contains a y-series diphthong?

┌──────────────────────────────────┐
│  A) 봐요                         │
│  B) 요리                         │
│  C) 외국                         │
│  D) 의사                         │
│                                  │
│  Answer: ____                    │
└──────────────────────────────────┘

Q2. How is '의' pronounced in "나의"?

┌──────────────────────────────────┐
│  A) [ɯi]                         │
│  B) [i]                          │
│  C) [e]                          │
│  D) [wi]                         │
│                                  │
│  Answer: ____                    │
└──────────────────────────────────┘

Q3. Which statement about ㅚ and ㅟ is correct?

┌──────────────────────────────────┐
│  A) They were always diphthongs  │
│  B) They are monophthongs in     │
│     standard pronunciation, but  │
│     most modern speakers         │
│     pronounce them as diphthongs │
│  C) They weren't covered in      │
│     Week 2                       │
│  D) They are w-series diphthongs │
│                                  │
│  Answer: ____                    │
└──────────────────────────────────┘

Q4. Which two vowels combine to form ㅘ?

┌──────────────────────────────────┐
│  A) ㅜ + ㅓ                      │
│  B) ㅗ + ㅏ                      │
│  C) ㅗ + ㅐ                      │
│  D) ㅜ + ㅔ                      │
│                                  │
│  Answer: ____                    │
└──────────────────────────────────┘

(Answers: Q1-B, Q2-C, Q3-B, Q4-B)

Activity Answer Key

Activity 1 — Monophthong → y-Series Conversion

ㅏ [a]  →  ㅑ     (야구)
ㅓ [ʌ]  →  ㅕ     (여기)
ㅗ [o]  →  ㅛ     (요리)
ㅜ [u]  →  ㅠ     (유리)

Activity 2 — Spot the w-Series Vowel

과자  →  w-series vowel: ㅘ
돼지  →  w-series vowel: ㅙ
줘    →  w-series vowel: ㅝ
웨딩  →  w-series vowel: ㅞ

Activity 3 — Choose the Modern Pronunciation of ㅚ and ㅟ

① 외국인 — modern pronunciation of ㅚ:  (B) [we]
② 귀여워 — modern pronunciation of ㅟ:  (C) [wi]
③ Modern pronunciations of 왜 and 외:  (B) Both pronounced [we]

Activity 4 — Applying the ㅢ Pronunciation Rules

① 의자 (first syllable)    →  [ɯi]
② 주의 (middle syllable)   →  [i]
③ 희의 (particle)          →  [e]
④ 의원 (first syllable)    →  [ɯi]

Activity 5 — Diphthong Sorting Challenge

┌──────────────────────────┬────────────────────────────┐
│ Type                      │ Vowels                     │
├──────────────────────────┼────────────────────────────┤
│ y-series                  │ ㅑ  ㅕ  ㅛ  ㅠ             │
├──────────────────────────┼────────────────────────────┤
│ w-series                  │ ㅘ  ㅙ  ㅝ  ㅞ             │
├──────────────────────────┼────────────────────────────┤
│ Monophthong → Diphthong   │ ㅚ  ㅟ                     │
├──────────────────────────┼────────────────────────────┤
│ One-of-a-kind diphthong   │ ㅢ                         │
└──────────────────────────┴────────────────────────────┘

Activity 6 — Reading Vowels in Context

① 야구:  ㅑ → diphthong  /  ㅜ → monophthong
② 외국:  ㅚ → diphthong (by modern pronunciation)
③ 의사:  ㅢ → diphthong  /  ㅏ → monophthong
④ 유리:  ㅠ → diphthong  /  ㅣ → monophthong
⑤ 봐요:  ㅘ → diphthong  /  ㅛ → diphthong

What You Learned This Week

A diphthong is a vowel where your mouth shape shifts while the sound plays
4 y-series vowels: ㅑ[ja] ㅕ[jʌ] ㅛ[jo] ㅠ[ju] — glide [j] + monophthong
4 w-series vowels: ㅘ[wa] ㅙ[wɛ] ㅝ[wʌ] ㅞ[we] — glide [w] + monophthong
ㅙ[wɛ] and ㅞ[we] are pronounced identically as [we] by most modern speakers
ㅚ and ㅟ: officially monophthongs, but modern speakers pronounce them as diphthongs ([we] and [wi])
ㅢ[ɯi]: a one-of-a-kind diphthong — not y-series, not w-series
ㅢ has three pronunciations depending on position: [ɯi] / [i] / [e]
Monophthongs (10) + Diphthongs (11) = the complete Korean vowel system

"Next week: Putting it all together — reading real K-pop and K-drama words and sentences. Everything from the past 7 weeks, finally in the wild."

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