Korean ㅡ vs ㅜ: Sounds, Rules and Examples

What you'll learn

• Say 으 and 우 with the correct lip shape, using a smile-and-pucker routine.
• Choose between 그 (that) and 구 (nine), and between 글 (writing) and 굴 (oyster), by ear.
• Explain why Revised Romanization writes ㅡ as "eu" without any French sound.
• Fix the most common substitution, saying ㅡ as ㅓ.

Before you start: review Korean Simple Vowels. The lesson takes about 20 minutes, and audio plays only when you press a button.

What Is the Korean ㅡ vs ㅜ Difference?

The Korean ㅡ vs ㅜ difference is spread lips versus rounded lips. For ㅡ, the corners of the mouth pull to the sides as in a flat smile. For ㅜ, the lips push forward into a small circle. The tongue sits high at the back of the mouth for both, so the lips alone separate the two vowels.

Listen to the two letter names.

The first clip is 으 (the letter ㅡ) and the second is 우 (the letter ㅜ). In the standard language described by the 국립국어원 (National Institute of Korean Language), both are separate vowels, and many everyday words depend on the difference, such as 그 (that) and 구 (nine). This is a contrast that you can hear, unlike ㅐ and ㅔ.

Why do English speakers get this pair wrong? The next section explains.

Why English Speakers Struggle with ㅡ and ㅜ

English speakers struggle with ㅡ because English has no vowel with a high back tongue and spread lips. They replace it with the nearest sound, which is usually the "uh" of "cut" or the vowel of "put", and those sounds are closer to ㅓ or a weak form of ㅜ. They also struggle with ㅜ because English "oo" often glides forward and ends with a "w".

Three patterns appear again and again:

• ㅡ becomes ㅓ. The jaw opens and the tongue drops, so 크다 sounds like 커다.
• ㅡ becomes ㅜ. The lips round by habit, so 그 sounds like 구.
• ㅜ becomes "oo-w". The vowel glides, so 우 sounds like English "woo".

The fix for all three is to control the lips first and the jaw second. The next section builds ㅡ from nothing.

What Is the Sound of ㅡ?

ㅡ is a high back unrounded vowel. Keep the jaw almost closed, pull the tongue back and up, and spread the lips so the corners reach toward the ears. The sound is steady, tense and flat. It is the same vowel Korean inserts into English words with consonant clusters, as in 스트레스 (stress).

Hear it in a common word.

크다 (keuda) means "to be big". The vowel in 크 is ㅡ, and the consonant ㅋ is aspirated. Say it slowly and keep your lips flat. If the lips round, you get 쿠다, which is not a word. If the jaw drops, you get 커다, which is a different vowel.

Expert insight: the vowel ㅡ is the hardest Korean vowel for many English speakers, yet it appears in very common words such as 으뜸 (the best), 이름 (name) and 그 (that). A few minutes of daily lip work pays back quickly.

Now the rounded partner.

What Is the Sound of ㅜ?

ㅜ is a high back rounded vowel, close to the "oo" in English "food" but steady. Round the lips tightly, push them forward and raise the back of the tongue. Do not let the vowel end in a "w". The sound is shorter and tighter than the English one, with no glide.

A common comparison is the "oo" in "book", but that English vowel is lax and lower. For ㅜ, the lips should be rounder and the tongue higher.

The word 우유 (uyu, milk) has ㅜ in both syllables. Say it with two identical rounded shapes. If the lips relax between the syllables, the second ㅜ will sound like ㅡ. Keep the same shape twice.

Now the movement between the two vowels.

How Do You Move from ㅜ to ㅡ?

Move from ㅜ to ㅡ by keeping the tongue still and changing only the lips. Because the tongue stays high and back for both vowels, you can switch between them with a smile and a pucker. This routine is the most useful physical cue in this lesson.

1. Say 우. Round the lips into a small circle and hold a steady "oo".
2. Keep the tongue still. Do not move the tongue or the jaw.
3. Spread the lips. Pull the corners of the mouth to the sides, as if smiling for a photo.
4. Listen. The sound changes to 으 with no other movement.
5. Reverse. Return to a pucker and hear 우 again.

If the sound changes into "uh", the jaw moved. If the sound changes into "ee", the tongue moved forward. A second route starts from "ee": say a smiling "ee", then pull the tongue back without moving the lips, and you arrive at 으.

A mirror helps. In step 3, the lips should look wider than usual, and in step 1 they should look smaller than usual. The shapes are exaggerated at first, then relax with practice, and a relaxed version of each shape is what native speakers produce.

Next, the three-way comparison. Every Korean learner meets this trio, and a table makes it easy to see.

How Do ㅡ, ㅜ and ㅓ Compare?

ㅡ, ㅜ and ㅓ form a trio that learners mix up, and the lips and jaw separate all three. The tongue is high and back for ㅡ and ㅜ, and lower for ㅓ. The lips are spread for ㅡ, rounded for ㅜ and relaxed for ㅓ.

Read the table by column. Jaw tells you ㅡ and ㅜ against ㅓ, and lips tell you ㅡ against ㅜ. A learner who says ㅡ with an open jaw has moved from the ㅡ row to the ㅓ row. The slip in the last row, rounding ㅓ into ㅗ, is covered in the ㅓ versus ㅗ lesson.

A five-minute daily plan keeps this practical. Spend one minute on the smile-and-pucker switch, two minutes on the word pairs in front of a mirror, one minute on a recorded sample of 크다 and 우유, and one minute listening to the clips again. Short daily sessions fix lip habits better than one long weekly session. This plan is a suggestion from teaching practice, not a tested method, so adjust it to what you notice in the mirror.

With the trio clear, the sound can be tested in real words. A limit applies here: a table describes tendencies, and individual voices vary, so use the clips and a mirror as the final check.

Which Words Test the Pair?

Words that differ only in ㅡ and ㅜ are minimal pairs. The table lists real words and one clearly labelled syllable pair.

The syllable 슬 does not stand alone as a common word, so the pair is more precisely 슬프다 (sad) and 술 (alcohol). More pairs, with an answer key, are in vowel minimal pairs.

Listen to the first pair.

These clips are 그 (that) and 구 (nine). Say them with a smile for 그 and a pucker for 구. The sounds are one-syllable words, so the lip change must happen fast. Next, where else the sound shows up.

ㅡ in Loanwords and Everyday Words

ㅡ is the vowel Korean uses to break up English consonant clusters, so it appears in many loanwords. English "stress" has three consonants in a row at the start, but Korean syllables cannot hold that, so the language adds ㅡ: 스트레스. The same pattern gives 스키 (ski), 크리스마스 (Christmas) and 프로 (pro).

The word 으뜸 (eutteum) means "the best" or "the top". It begins with the syllable 으, written with the silent consonant ㅇ in front of ㅡ. The ㅇ makes no sound at the start of a syllable, so what you hear is only the vowel.

Because ㅡ is often short in these loanwords, it can sound almost silent in fast speech. It never disappears completely in careful speech. The next section applies the lip routine to one pair.

Worked Example: 술

This worked example uses 술 (alcohol) and 슬프다 (to be sad) to practise the pair 으 and 우. Follow the steps in order.

1. Say 우, then 으. Use the smile-and-pucker routine to feel the lips switch.
2. Add the consonants. ㅅ and ㄹ are the same in both words, so only the vowel changes.
3. Say 술. Pucker the lips for ㅜ.

4. Say 슬프다. Spread the lips for ㅡ in the first syllable.

5. Check the lips. In 술 they should be small and round. In 슬프다 they should be wide and flat.
6. Check the meaning. 술 is a drink containing alcohol. 슬프다 describes sadness, and its stem 슬 has the vowel ㅡ.

On a keyboard, ㅡ is the M key and ㅜ is the N key on the standard Korean layout. The next section lists the mistakes that matter most.

Common Learner Mistakes

Learners often assume that ㅡ is an English "uh". Actually the jaw is nearly closed and the lips are spread. English "uh" has the jaw open and the lips relaxed, so it is closer to ㅓ. Using "uh" turns 크다 into something like 커다, and listeners hear the wrong vowel.

Four more mistakes:

• Learners often assume that ㅡ is the French "eu". Actually Revised Romanization uses "eu" as a convention. The French vowel has rounded lips, and ㅡ has spread lips.
• Learners often assume that ㅡ needs rounded lips like ㅜ. Actually the difference is exactly the lips. Spread them.
• Learners often assume that ㅜ is the "oo" in "book". Actually the English vowel is lower and looser. Round the lips more and raise the tongue.
• Learners often assume that long holding helps. Actually both vowels are steady but not long. Hold them only as long as needed.

Time to practise.

Practice and Answer Key

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

1. Meaning. Which word means "nine": 그 or 구?
2. Meaning. Which word means "alcohol": 술 or 슬?
3. Lips. You smile while saying 구 (nine). Which word did you really say?
4. Word. Which word means "milk": 으유 or 우유?
5. Mirror. Say 우유 and 크다 in a row. Do your lips change from round to flat?

Answer key: 1. 구. 2. 술 (슬 alone is the first syllable of 슬프다, to be sad). 3. 그 (that), because spreading the lips turns ㅜ into ㅡ. 4. 우유. 5. The lips should round for 우유 and flatten for 크다.

Common questions follow.

Frequently Asked Questions

Is ㅡ like the "oo" in book? No. The English "oo" in "book" uses rounded lips, while ㅡ uses spread lips. They share a high back tongue, which is why they feel related. Start from the rounded vowel and change only the lips: pucker for ㅜ, smile for ㅡ. If your lips stay round, the sound is not ㅡ.

How do I make the ㅡ sound? Say a steady "oo" with rounded lips, then spread the lips into a smile without moving the tongue or jaw. The sound changes into ㅡ. Another route is to say "ee" and pull the tongue back while keeping the smile. Check the shape with a mirror, and compare your sound with the clips.

Why do I say ㅡ as ㅓ? English has no vowel like ㅡ, so learners substitute the closest unrounded vowel, "uh", which is nearer to ㅓ. The cause is jaw position. ㅓ uses a half-open jaw, and ㅡ uses an almost closed one. Close the jaw, spread the lips, and keep the tongue high and back.

Is ㅡ ever silent? The letter ㅡ is not silent, but the consonant ㅇ is silent at the start of a syllable, so 으 sounds like ㅡ alone. In fast speech ㅡ can become very short, especially in loanwords such as 스트레스. In careful speech it is always present, so practise it as a full vowel.

Where to Go Next

Korean ㅡ vs ㅜ comes down to smile versus pucker, so practise the routine daily. This lesson does not cover other vowel contrasts, such as ㅓ and ㅗ, or the ㅢ vowel that begins with ㅡ. It also does not score your pronunciation. Read about the other hard back-vowel pair in ㅓ versus ㅗ, find the letters in Korean vowels, and return to Korean Vowel Sounds for the whole section.

Next in the series: Korean ㅐ vs ㅔ Pronunciation.

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