Diphthong Meaning in Korean
A diphthong is a "two-part" vowel. The mouth starts in one position and travels to another while the syllable lasts. In Korean the first part is almost always a quick y or w, called a glide or semivowel (반모음). The second part is a normal steady vowel. So ㅑ is a quick y followed by ㅏ.
Korean has two glide families, and the pattern shows in the letter shapes.
| Family | Letters | Glide + vowel | Example |
|---|---|---|---|
| y-glide | ㅑ ㅕ ㅛ ㅠ | y + ㅏ ㅓ ㅗ ㅜ | 야구 (baseball) |
| y-glide, wide | ㅒ ㅖ | y + ㅐ ㅔ | 예의 (manners) |
| w-glide | ㅘ ㅝ ㅙ ㅞ | w + ㅏ ㅓ ㅐ ㅔ | 과일 (fruit) |
| w-glide, often | ㅚ ㅟ | w + ㅔ, w + ㅣ | 귀 (ear) |
| special | ㅢ | no simple analysis | 의사 (doctor) |
A writing shortcut helps with the y-glides: an extra short stroke on the vowel marks the y. ㅏ becomes ㅑ and ㅓ becomes ㅕ. Article 5 of the Standard Pronunciation Rules (표준 발음법) lists eleven diphthongs, and Article 4 allows ㅚ and ㅟ to be pronounced as diphthongs too, which is why guides count either eleven or thirteen. Hear the y-glide in 야구.
The glides are covered in their own entry, glide. With the pattern clear, the next job is to separate diphthongs from the steady vowels.
Diphthong Versus Monophthong
A diphthong moves from one mouth position to another, while a monophthong stays in one position. The table lines up one pair that differs only by a glide.
| Feature | Diphthong | Monophthong |
|---|---|---|
| Mouth movement | glides | none |
| Korean term | 이중모음 | 단모음 |
| Example pair | 야 (ya) | 아 (a) |
| Written clue | extra stroke or two vowels joined | single vowel shape |
The written clue is useful: ㅘ is ㅗ and ㅏ joined, and ㅙ is ㅗ and ㅐ joined, so the shape records the glide. For the steady side of the table, see monophthong. Examples follow.
What Are Examples of Diphthongs?
Three words show a y-glide, a w-glide and the special vowel ㅢ.
야구
yagu
baseball
과일
gwail
fruit
의사
uisa
doctor
In 야구 the ㅑ starts with a y, as in English "yacht". In 과일 the ㅘ starts with a w, as in "want". In 의사 the ㅢ is pronounced [의], a vowel that moves from ㅡ to ㅣ. Those three show the main patterns, and the full set is in the lesson on Korean diphthongs. The mistakes below come from the same patterns.
What Do Learners Get Wrong about Diphthongs?
Learners often assume that ㅑ is pronounced as two syllables, "ee-ah". It is one syllable, with a glide so brief that the y is hardly a full vowel. If you say two beats, the word sounds slower than normal Korean speech.
Two other points need care:
- Assuming ㅢ is always [의]. The vowel is [의] at the start of a word, [이] after a consonant, as in 희망 [히망], and may be [에] as a possessive particle. In a later syllable without a consonant before it, [이] is also allowed, as in 주의 [주의] or [주이]. Article 5 of the Standard Pronunciation Rules sets out all of these.
- Assuming ㅚ and ㅟ are fixed. They can be single vowels or diphthongs depending on the speaker and the guide. Most Seoul speakers use a glide, so train with the glide first.
Remember that a diphthong is one syllable with a moving vowel. The questions below follow from that.
Frequently Asked Questions
What is a diphthong? A diphthong is a vowel sound that moves from one mouth position to another within a single syllable. The English word "boy" has one. In Korean, a diphthong usually begins with a very short y or w sound and settles into a vowel, as in ㅑ (ya) and ㅘ (wa). Korean calls them 이중모음.
How many diphthongs are there in Korean? The Standard Pronunciation Rules list eleven: ㅑ ㅒ ㅕ ㅖ ㅘ ㅙ ㅛ ㅝ ㅞ ㅠ ㅢ. If you add ㅚ and ㅟ, which are also commonly said with a glide, the total is thirteen. Guides vary, so the count depends on whether the guide treats ㅚ and ㅟ as single vowels.
Is ㅢ a diphthong? Yes, but it behaves differently from the others. ㅢ is pronounced [의] at the start of a word, as in 의사. After a consonant, as in 희망, it is pronounced [이]. As the possessive particle 의, it may be pronounced [에]. This variation is why ㅢ gets a separate note in most vowel lessons.
What is 이중모음? 이중모음 (ijungmoeum) is the Korean term for diphthong. The word combines 이중, meaning "double", with 모음, meaning "vowel". The counterpart is 단모음 (danmoeum), which means monophthong. You will meet both words in Korean grammar books, in the Standard Pronunciation Rules and in the vowel lessons on this site.
Related Terms and Lessons
Diphthong meaning rests on two other terms, the glide and the monophthong, and on the lesson about Korean diphthongs. Every sound term is listed in the Korean Pronunciation Glossary.
