Korean Diphthongs: Sounds, Rules and Examples

What you'll learn

• Sort the Korean diphthongs into y-glides, w-glides and ㅢ.
• Pronounce one example word from each group, such as 야구, 와요 and 의사.
• Explain why 쳐 is pronounced like 처 in verb forms.
• Read the letter counts (10, 11, 13, 21) without confusion.

Before you start: review Korean Simple Vowels, because every glide ends in a simple vowel. The lesson takes about 20 minutes, and audio plays only when you press a button.

Key facts

• The English words "yes" and "yawn", and "water" and "wing", show the same glides.

What Are Korean Diphthongs?

Korean diphthongs are vowel sounds that begin with a short glide, either y or w, and end in a steady vowel. A glide, also called a semivowel, is a very quick vowel-like sound that leads into the next vowel. The y-glide in ㅑ is the "y" of English "yard", and the w-glide in ㅘ is the "w" of English "water".

Hear three of them in everyday words.

The clips are 여자 (woman), 요리 (cooking) and 유리 (glass). Each starts with a quick "y" and then holds a steady vowel. Linguists call the pattern glide plus vowel, and Korean tradition calls these letters 이중 모음, or "double vowels".

The thirteen glide vowels fall into three groups, and the group tells you how to say each one. First, why this is easier than it looks.

Why English Speakers Struggle with Korean Diphthongs

English speakers struggle less with Korean glides than with other Korean sounds, because English already has "y" and "w". The real difficulty is that the learner treats each glide letter as a new, unknown vowel. Another difficulty is that Korean spells several glides differently that sound the same, so the eye sees more differences than the ear hears.

Three habits cause most errors:

• Long glides. The y or w lasts too long, so 야 sounds like "ee-ah".
• Wrong second vowel. Learners say ㅛ (yo) when they mean ㅕ (yeo), because both begin with a glide.
• Treating ㅢ as ordinary. The letter has several readings, and learners apply one of them everywhere.

Treat each glide as a small step in front of a vowel you already know. The next section shows how the steps work.

How Do Korean Glides Work?

A Korean glide works by starting the mouth in the position of ㅣ (for y) or ㅜ/ㅗ (for w) and moving quickly into the vowel that follows. The movement is fast and the vowel that follows carries the length. Only the second part is held.

The letters follow this logic. The basic y-glide letters add a second short stroke to a simple vowel, and each w-glide joins two vowel letters.

How many diphthongs does Korean have? The answer depends on how you count, and four counts appear in books and websites.

The two lists of 11 are different. The standard's list puts ㅚ and ㅟ with the single vowels, while Korean compound vowels groups letters by how they are built. This lesson uses 13 because ㅚ and ㅟ are usually heard as glides in Seoul speech. Now the first group.

Which Letters Are Y-Glides?

The y-glide vowels are ㅑ, ㅕ, ㅛ, ㅠ, ㅒ and ㅖ, six letters that each begin with the y sound. The first four add a stroke to ㅏ, ㅓ, ㅗ and ㅜ. The last two add ㅣ.

The vowel after the glide keeps its simple-vowel shape. So ㅛ is a quick "y" followed by ㅗ, with rounded lips, and ㅕ is a quick "y" followed by ㅓ, with relaxed lips. This is why ㅛ and ㅕ differ in the same way that ㅗ and ㅓ differ, as explained in ㅓ versus ㅗ. The letters ㅒ and ㅖ sound alike for most speakers.

For the full lesson, see y-glide vowels. Now the other group.

Which Letters Are W-Glides?

The w-glide vowels are ㅘ, ㅝ, ㅙ, ㅞ, ㅚ and ㅟ, six letters that begin with a quick w sound. Each is built from ㅗ or ㅜ followed by another vowel letter.

Hear three of them.

The clips are 와요 (comes), 원 (won) and 위 (above). Most Seoul speakers say ㅙ, ㅞ and ㅚ almost the same, a "we" sound, so these three differ mainly in spelling. That group is the subject of vowels that sound the same. For the full lesson, see w-glide vowels. One vowel remains.

What Is Special about ㅢ?

ㅢ is special because it has several accepted pronunciations that depend on where it appears. It begins with ㅡ (spread lips) and glides to ㅣ. At the start of a word, as in 의사 (doctor), it is said as a quick ㅡ followed by ㅣ. After a consonant, as in 희망 (hope), it is said as ㅣ alone. As the possessive particle 의, it may be said as ㅔ.

The clip is 의사 (doctor). The details, with audio for each position, are in how to pronounce ㅢ. For now, remember that ㅢ is the one glide vowel that needs its own lesson. Now a rule that causes many misreadings of spelling.

The 져, 쪄, 쳐 Rule

In verb forms, 져, 쪄 and 쳐 are pronounced like 저, 쩌 and 처. For example, 가져요 (brings) is said [가저요], and 다쳐요 (gets hurt) is said [다처요]. The rule appears in the 표준 발음법 (Standard Pronunciation Rules), Article 5, as an exception to the general rule for ㅕ.

Why does this happen? The consonants ㅈ, ㅉ and ㅊ are made with the tongue against the roof of the mouth, close to the position of y. A separate y-glide after them adds nothing, so speakers drop it. In Seoul speech, ㅈ followed by ㅓ and by ㅕ sound the same, but the spelling stays. This is the first of several places where spelling and sound differ.

The rule also shows that glide letters can be silent in effect. When you write, still spell the word with the ㅕ. Next, how long a glide should last.

How Long Should the Glide Last?

The glide should last a fraction of the whole vowel, so short that the listener hears one syllable with a quick start. As a rule of thumb, spend most of the time on the second vowel. If you can hold the "y" or "w" for a full second, it is too long.

A drill makes this concrete. Say English "yes" and notice that the "y" is brief and the "e" is held. Now say 여자 with the same rhythm. Say English "wing" and then 위, again with a brief start. If the glide stretches, the word turns into two syllables, such as "ee-eo-ja".

Telling similar letters apart is the next problem.

Telling Similar Glide Letters Apart

Several glide letters look or sound close, and a table of the common mix-ups shortens the learning time. Each row pairs letters that learners confuse and names the cue that separates them.

Sets that differ in sound deserve ear training, and sets that differ only in spelling deserve memory work. The first kind connects to vowel minimal pairs. The second kind connects to the spelling advice in the ㅐ and ㅔ lesson. Now one word in detail.

Worked Example: 야구

This worked example takes 야구 (baseball) apart from letter to sound. Do the steps in order.

1. Spot the glide. The first syllable, 야, is ㅇ + ㅑ. The ㅇ is silent, and ㅑ is the y-glide plus ㅏ.
2. Say the glide. Make the "y" of English "yard", and stop there for a moment.
3. Add the vowel. Slide quickly into a wide-open ㅏ. The glide should last a fraction of the vowel.
4. Say the second syllable. 구 is ㄱ + ㅜ, with rounded lips.
5. Join them.

6. Check the meaning. 야구 is baseball, a popular sport in Korea.

The same two parts, a quick glide and a held vowel, work for 여자, 요리 and 유리. The reverse mistake is to hold the y and shorten the vowel. Next, the errors that matter most.

Common Learner Mistakes

Learners often assume that ㅕ is pronounced like "yo". Actually ㅕ is a "y" followed by ㅓ, with relaxed lips, while ㅛ uses rounded lips. The result of mixing them is that 여자 (woman) sounds like 요자, which is not a word.

Four more mistakes:

• Learners often assume that the glide must be long. Actually it is short, and the vowel carries the length.
• Learners often assume that every spelling has its own sound. Actually ㅒ and ㅖ, and ㅙ ㅞ ㅚ, sound alike for most speakers.
• Learners often assume that ㅟ must be a rounded front vowel, like French "u". Actually the standard allows that, but Seoul speech usually uses a quick w plus ㅣ, like "wee".
• Learners often assume that ㅢ has one sound. Actually it changes with position, so learn it as a separate case.

Test yourself now.

Practice and Answer Key

Do these exercises after listening. Cover the answer key until you finish.

1. Group. Is ㅠ a y-glide, a w-glide or ㅢ?
2. Group. Is ㅟ a y-glide, a w-glide or ㅢ?
3. Word. Which word means "woman": 여자 or 요자?
4. Built from. Which two letters make up ㅘ?
5. Rule. How is 다쳐요 pronounced?

Answer key: 1. A y-glide. 2. A w-glide. 3. 여자. 4. ㅗ and ㅏ. 5. [다처요].

Common questions follow.

Frequently Asked Questions

How many diphthongs does Korean have? It depends on the count. The standard lists 11 "double vowels", and this lesson counts 13 glide vowels by adding ㅚ and ㅟ. Together with the eight simple vowels, the 13 give 21 vowel letters. Learners can ignore the debate: pronounce the glide, then the vowel.

Is ㅢ a diphthong? Yes, it is a glide vowel, but it is a special one. It begins with ㅡ and moves to ㅣ at the start of a word. After a consonant or as a possessive, it is often said as ㅣ or ㅔ. Learn it as a separate case in its own lesson.

Why is 쳐 pronounced 처? The consonants ㅈ, ㅉ and ㅊ already involve the tongue position of the y sound, so a following y-glide adds nothing. The Standard Pronunciation Rules state that 져, 쪄 and 쳐 in verb forms are pronounced 저, 쩌 and 처. The spelling still keeps ㅕ.

Are diphthongs hard for English speakers? Less than most Korean sounds, because English has "y" and "w" glides. The difficulty is keeping the glide short and choosing the right second vowel, such as ㅕ versus ㅛ. Practise one anchor word per vowel, such as 야구, 여자, 요리 and 유리, and the system looks small.

Where to Go Next

Korean diphthongs are 13 vowels that follow one pattern, a short glide plus a held vowel. This lesson does not teach each vowel in detail, it does not cover every regional variation of ㅢ, ㅚ and ㅟ, and it does not score your speech. Where a letter has more than one accepted reading, the page gives the Seoul reading that learners meet most often, and Min-ji Park reviewed and signed off that reading on 15 October 2026. Continue with the y-glide vowels, the w-glide vowels and how to pronounce ㅢ. For the term itself, see the diphthong glossary entry, and return to Korean Vowel Sounds for the section overview.

Next in the series: Korean Y Vowels ㅑ ㅕ ㅛ ㅠ.

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