Korean N Insertion Rules: Sounds, Rules and Examples

What you will learn

• Apply the rule to 한여름, 색연필, 담요, 맨입 and 식용유 and say them aloud.
• Name the five vowels that trigger the rule.
• Use a four-step test to decide whether a new word gets an extra ㄴ.
• Follow the chain from the inserted ㄴ to nasalization in 색연필 and 꽃잎.

Before you start: you know how ㄱ, ㄷ and ㅂ become ㅇ, ㄴ and ㅁ before ㄴ, from the Nasalization section. Time: about 30 minutes with audio.

Key Facts

• In a compound, when the first part ends in a consonant and the second part starts with 이, 야, 여, 요 or 유, an extra ㄴ sound is added: 한여름 is [한녀름].
• The extra ㄴ is never written; the spelling stays 한여름, 담요 and 맨입.
• The inserted ㄴ can trigger nasalization of the final before it: 색연필 is [생년필] and 꽃잎 is [꼰닙].
• Particles and endings do not trigger the rule: 책이 is [채기], not [챙니].
• After ㄹ, the inserted ㄴ becomes ㄹ: 알약 is [알략]. That case has its own lesson.
• The rule is Article 29 of the Standard Pronunciation Rules (표준 발음법), which also lists optional and exceptional words.

Last updated: 2026-10-09. The Korean text, romanization and audio scripts on this page are generated drafts that still await review by a Korean specialist.

What Are the Korean N Insertion Rules?

The Korean n insertion rules describe a sound that appears in speech but not in spelling. Linguists call this kind of change epenthesis, which means inserting a sound. In Korean the inserted sound is always ㄴ, and grammar books call the change ㄴ 첨가 (adding ㄴ).

A common explanation lies in the vowels involved. 이, 야, 여, 요 and 유 all begin with the tongue high and forward in the mouth, in the "ee" or "y" position. When a consonant ends the first word part and one of these vowels starts the second, speakers slip an n-like sound into the gap.

Revised Romanization (RR) writes the inserted sound, so 한여름 is hannyeoreum with nny. The RR rules list this as one of the sound changes that romanization follows. RR is a learning aid on this page; the Hangul and the bracketed forms are the reference. The next section explains why the rule trips up careful readers.

Why Learners Read 한여름 as "Han-Yeo-Reum"

Learners read 한여름 as "han-yeo-reum" because they know liaison, the rule that moves a final consonant into a following vowel. Liaison would give *[하녀름], and plain reading gives *[한여름]. Neither matches what Koreans say, which is [한녀름], with the ㄴ heard twice.

The spelling gives no clue. Nothing in 한여름 shows the extra ㄴ, and the same letters ㄴ + 여 appear in words where nothing is inserted. A learner needs a rule that looks at the meaning of the word parts, not only at the letters.

That rule has two parts: which sounds trigger it, and which word boundaries allow it. The trigger comes first.

What Does N-Insertion Do?

N-insertion adds a ㄴ at the start of the second word part, so that the vowel 이 becomes [니], 야 becomes [냐], 여 becomes [녀], 요 becomes [뇨] and 유 becomes [뉴]. The final consonant of the first part stays where it is. Article 29 of the Standard Pronunciation Rules (표준 발음법), published by the National Institute of Korean Language (국립국어원), states the rule.

Compare the result with liaison. Liaison moves a consonant: 밤이 (the night, as subject) is [바미]. N-insertion keeps the consonant and adds one: 밤일 (night work) is [밤닐]. The difference between the two words is the meaning of the second part, which the next sections turn into a test.

Which Sounds Trigger It?

Only five vowels trigger n-insertion: 이, 야, 여, 요 and 유. These are the vowel ㅣ and the four vowels that begin with a y-glide. A glide is a quick, vowel-like sound that leads into the main vowel, like the y in "yes".

Other vowels never trigger it. 밤 + 안개 (fog) gives 밤안개 (night fog), and no ㄴ is added; the ㅁ simply links forward: [바만개]. If the second part starts with 아, 어, 오, 우, 으 or 애, look for a different rule. The trigger is necessary but not enough, so the next question is where the boundary must be.

When Does the Rule Apply?

The rule applies only at a boundary between two meaningful word parts, such as in a compound or after a prefix. Use this four-step test on any new word:

1. Check the first part. It must end in a consonant, for example 한 or 색.
2. Check the second part. It must start with 이, 야, 여, 요 or 유.
3. Check the meaning. The second part must be a word or suffix with its own meaning, such as 여름 (summer), 연필 (pencil) or 잎 (leaf). A particle (이, 은, 을) or a verb ending (-어요, -으면) fails this step.
4. Add the ㄴ, then apply any further rule that the new ㄴ triggers.

If step 3 fails, use liaison instead. 색이 (the colour, as subject) is [새기], because 이 is a particle. 색연필 is [생년필], because 연필 is a noun. The fourth step often changes more than the second part, as the next section shows.

What Happens to the Final Consonant?

The final consonant before the inserted ㄴ often changes too, because the new ㄴ triggers nasalization. A stop final such as ㄱ, ㄷ or ㅂ cannot stand before ㄴ in Korean, so it becomes the matching nasal: ㄱ → ㅇ, ㄷ → ㄴ, ㅂ → ㅁ.

Follow the chain in 색연필:

1. Insert ㄴ: 색 + 연필 → 색 + [년필].
2. Nasalize the final: ㄱ before ㄴ → ㅇ, so 색 → [생].
3. Result: [생년필].

Follow the chain in 꽃잎 (petal):

1. Insert ㄴ: 꽃 + 잎 → 꽃 + [닙].
2. Reduce the final: ㅊ at the end of a syllable sounds [ㄷ], so 꽃 → [꼳].
3. Nasalize the final: [ㄷ] before ㄴ → ㄴ, so [꼳] → [꼰].
4. Result: [꼰닙].

The same chain gives 막일 (manual labour) [망닐] and 홑이불 (a single-layer quilt cover) [혼니불]. If the final is ㄹ, the inserted ㄴ becomes ㄹ instead, as in 알약 [알략]; that case is covered in n-insertion after ㄹ. The chain is the reason this rule is taught after Korean nasalization. A larger set of words makes the groups clear.

Twelve Compounds in Three Groups

Grouping compounds by the final consonant of the first part shows what happens after insertion. Group A needs nothing more. Group B adds nasalization. Group C, after ㄹ, belongs to the next lesson.

Group A: final ㄴ, ㅁ or ㅇ (insertion only)

Group B: final stop (insertion, then nasalization)

Group C: final ㄹ (insertion, then ㄴ → ㄹ)

In 식용유, liaison and insertion happen in the same word: the ㄱ of 식 moves into 용, giving [시굥], and then ㄴ is added before 유. The groups make it easy to predict the sound once you know the final. The harder question is when not to insert at all.

N-Insertion or Liaison?

N-insertion and liaison are both triggered by a vowel, so learners often confuse them. The deciding factor is the second part: a meaning word allows insertion, while a grammar piece or a non-separable word gets liaison.

Expert tip: ask whether a Korean speaker would feel the second part as a separate word. 연필 and 여름 clearly are, so ㄴ is added. 금요일 is felt as one word, so it is not. Even native speakers disagree on a few words, which is the subject of the next section.

Optional Forms and Phrases

Article 29 lists some words where both pronunciations are standard. 금융 (finance) can be [금늉] or [그뮹], 검열 (censorship) can be [검녈] or [거멸], and 야금야금 (bit by bit) can be [야금냐금] or [야그먀금]. For these words, either form is correct.

N-insertion also applies between two words said as one unit: 한 일 (a thing done) can be [한닐] and 옷 입다 (to put on clothes) is [온닙따]. Number words built the same way follow it too: 서른여섯 (thirty-six) is [서른녀섣]. A pause between separate words stops the change.

There are also words that refuse the rule even though they pass the four-step test, such as 6·25 (the Korean War date), read [유기오], and 송별연 (farewell party), read [송벼련]. These are collected in n-insertion exceptions. The honest limit of this lesson is that the meaning test is a strong guide, not a guarantee, and the Standard Korean Language Dictionary (표준국어대사전) is the final authority for any single word.

Worked Example: 한여름

The word 한여름 is the prefix 한- (the peak of) plus the noun 여름 (summer), and it is spoken [한녀름]. It is the clearest example because no other rule interferes.

1. Split into parts: 한 / 여름.
2. Check the first part: 한 ends in the consonant ㄴ.
3. Check the second part: 여름 starts with 여, one of the five trigger vowels.
4. Check the meaning: 여름 is a noun with its own meaning, so the boundary allows insertion.
5. Add the ㄴ: 여 becomes [녀], giving [한녀름].
6. Check for a chain: the final ㄴ of 한 is already a nasal, so nothing else changes.

You will know it worked when you hear n at the end of 한 and again at the start of 녀, with no y-sound on its own. If you said [하녀름], you used liaison and lost the ㄴ of 한. The mistakes below are the common ones.

Common Learner Mistakes

Learners often treat any consonant before a vowel as a liaison case. The mistakes below come from that habit.

• Mistake 1: liaison in a compound. Learners often say 맨입 as *[매닙]. Actually the second part 입 is a noun, so ㄴ is inserted and the final stays: [맨닙].
• Mistake 2: insertion before a particle. Learners who have just learned the rule often say 책이 as *[챙니]. Actually 이 is a particle, so liaison applies: [채기].
• Mistake 3: forgetting the chain. Learners often say 색연필 as *[색년필]. Actually ㄱ before the inserted ㄴ must become ㅇ: [생년필].
• Mistake 4: writing the sound. Learners often write 담뇨 in dictation. Actually the spelling stays 담요, because the inserted ㄴ is never written.
• Mistake 5: inserting before any vowel. Learners sometimes add ㄴ before 아 or 오. Actually only 이, 야, 여, 요 and 유 trigger the rule.

Rule of thumb: consonant + meaning word starting with i or y → add n. The practice set checks the rule and the traps.

Practice and Answer Key

Write the spoken form of each word in brackets. Two items do not take an extra ㄴ.

1. 한여름
2. 담요
3. 맨입
4. 색연필
5. 식용유
6. 꽃잎
7. 막일
8. 책이
9. 눈요기
10. 금요일

Answer key

1. 한여름 → [한녀름]
2. 담요 → [담뇨]
3. 맨입 → [맨닙]
4. 색연필 → [생년필]
5. 식용유 → [시굥뉴]
6. 꽃잎 → [꼰닙]
7. 막일 → [망닐]
8. 책이 → [채기] (particle: liaison, no insertion)
9. 눈요기 → [눈뇨기]
10. 금요일 → [그묘일] (one word: liaison, no insertion)

Nine or ten correct means the rule is secure. If you missed 8 or 10, go back to the four-step test and check the meaning step.

Where to Go Next

The next lesson, Korean N Insertion with ㄹ, shows how the inserted ㄴ turns into ㄹ in 서울역 [서울력] and 알약 [알략]. Return to the N-Insertion section to see the lessons in order.

This lesson covers the core Korean n insertion rules in standard Seoul speech: the trigger vowels, the meaning test and the nasalization chain. It does not cover the full exception list, regional variation, or the history of the rule. The audio shows one standard pronunciation, and real speakers vary in speed.

Frequently Asked Questions

Why is 한여름 pronounced 한녀름? 한여름 (midsummer) is the prefix 한- (peak, middle) plus the noun 여름 (summer). The first part ends in ㄴ and the second starts with 여, so an extra ㄴ is inserted and 여 is said [녀]. The result is [한녀름]. Revised Romanization writes hannyeoreum, which shows the extra n.

Is the ㄴ written? No. The inserted ㄴ exists only in speech. 한여름, 색연필 and 담요 keep their original spelling, because Korean spelling (한글 맞춤법) writes each word part in its basic form. This is why dictation is hard: you hear [생년필] but must write 색연필. Dictionaries show the spoken form in brackets.

Does the particle 이 trigger n-insertion? No. The subject particle 이 is a grammar piece, not a word with its own meaning, so it triggers liaison instead. 책이 is [채기] and 밤이 is [바미]. N-insertion needs a second part with real meaning, such as 잎 (leaf) in 꽃잎 [꼰닙] or 여름 (summer) in 한여름.

What about 금요일? 금요일 (Friday) is [그묘일], with no inserted ㄴ. It is a single Sino-Korean word built from 금 (gold), 요 (day of the week) and 일 (day), and speakers do not split it like a compound. The ㅁ simply moves into 요 by liaison. 목요일 (Thursday) works the same way: [모교일].

Is 맨입 [맨닙] standard? Yes. 맨입 (an empty mouth, with nothing to eat or drink) is listed as [맨닙] in Article 29 of the Standard Pronunciation Rules. The prefix 맨- (bare) ends in ㄴ and 입 (mouth) starts with 이, so ㄴ is inserted. Saying [매닙] with plain liaison is a common learner error.