If you’ve been studying Korean for a while, you’ve probably noticed that sometimes the Korean letter ㅂ doesn’t sound exactly like a “b” or “p.” In some words, it even sounds like an “m.” For example, in “감사합니다 (gam-sa-ham-ni-da),” the ㅂ in “합니다” sounds more like “hamnida” than “hapnida.” Why does this happen?
Let’s explore the mystery behind the changing sound of ㅂ — and how Korean pronunciation rules make it logical once you understand them.
1. ㅂ: The “B” That Can Act Like a “P” or “M”
The Korean consonant ㅂ may look simple, but its sound changes slightly depending on where it appears in a word. Unlike English, which distinguishes between voiced b and voiceless p, Korean doesn’t separate them by voicing — instead, it distinguishes between aspirated (with a strong burst of air) and unaspirated (without much air) sounds.
The letter ㅂ is an unaspirated bilabial stop, which means it’s made by closing both lips tightly and releasing the air without a strong puff.
Here’s how it behaves depending on its position:
| Position | Sound | English Approximation | Example | Pronunciation |
|---|---|---|---|---|
| At the beginning of a word (초성) | Slightly voiceless, closer to [p] | Like p in “spoon” | 바다 (sea) | pada |
| Between vowels (중성) | More voiced, closer to [b] | Like b in “baby” | 아버지 (father) | abeoji |
| At the end of a syllable (받침) | Unreleased, short [p̚] | Like p in “stop” | 밥 (rice) | [pap̚] |
So while learners often think ㅂ = “b,” the truth is more nuanced. In Korean, ㅂ naturally shifts depending on its environment, and English ears perceive it differently depending on where it appears.
This flexible pronunciation is one reason Korean sounds smooth and rhythmical — it adapts subtly for easier flow between syllables.
2. Korean Pronunciation Rule: Nasal Assimilation (비음화)
The process that turns ㅂ → ㅁ is called nasal assimilation (비음화). It happens when a non-nasal consonant (like ㅂ, ㄷ, or ㄱ) is followed by a nasal consonant (like ㄴ or ㅁ).
Because Korean pronunciation flows smoothly, the mouth naturally shifts to make it easier to pronounce — so the sound changes!
Examples:
| Written | Pronounced | Meaning |
|---|---|---|
| 감사합니다 | 감사함니다 (gam-sa-ham-ni-da) | Thank you |
| 없습니다 | 업씀니다 (eop-seum-ni-da) | There isn’t / none |
| 입맛 | 임맛 (im-mat) | Appetite |
Try saying “hapnida” quickly — you’ll notice your lips want to close and make an “m” sound. That’s why Koreans say “hamnida” instead.
3. The Science Behind It: How Your Mouth Works
Let’s break it down physically:
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ㅂ (b/p) requires both lips closed.
-
ㄴ (n) and ㅁ (m) require the air to pass through the nose.
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When ㅂ is followed by ㅁ or ㄴ, your lips are already in the “closed” position for ㅂ — so the easiest transition is to stay with the nasal sound m.
In short, Korean speech naturally adjusts to make pronunciation smooth and efficient. This is not a random exception; it’s a consistent, rule-based change.
4. Common Assimilation Patterns
Here are a few more examples of how Korean sounds change for smoother pronunciation:
| Combination | Spoken As | Meaning | ||
|---|---|---|---|---|
| ㅂ + ㄴ | ㅂ → ㅁ | 감사합니다 → 감사함니다 | Thank you | |
| ㅂ + ㅁ | ㅂ → ㅁ | 입맛 → 임맛 | Appetite | |
| ㄷ + ㄴ | ㄷ → ㄴ | 맞나요 → 만나요 | Is that right? | |
| ㄱ + ㄴ | ㄱ → ㅇ | 숙녀 → 숭녀 | Lady | |
| ㅂ + ㄹ | ㅂ → ㅁ, ㄹ → ㄴ | 합리적 → 함니적 | Rational, reasonable |
This shows how phonological assimilation helps Koreans speak more fluidly — it’s all about ease of pronunciation!
5. Why This Matters for Learners
When learners see the word “합니다” written, they often pronounce it as hap-ni-da, which sounds stiff and unnatural. Native Koreans, however, never say it that way — they say ham-ni-da.
Understanding this rule will help your pronunciation sound much more natural and fluent. You don’t have to memorize every case individually — just remember:
If a syllable ending in ㅂ, ㄷ, or ㄱ is followed by ㄴ or ㅁ, change it to a nasal sound (ㅁ, ㄴ, ㅇ respectively).
That’s it! One rule explains dozens of pronunciation mysteries.
6. Practice with Real Sentences
Here are some sentences where this rule appears naturally:
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감사합니다 → gam-sa-ham-ni-da → “Thank you.”
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먹습니다 → meok-seum-ni-da → “(I) eat.”
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없습니다 → eop-seum-ni-da → “There is none.”
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입맛이 없어요. → im-ma-si eop-sseo-yo → “I don’t have an appetite.”
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합리적인 생각이에요. → ham-ni-jeo-gin saeng-ga-gi-e-yo → “That’s a reasonable thought.”
Read these aloud slowly at first, then naturally faster — your mouth will start adjusting automatically!
Conclusion
The change of ㅂ → ㅁ is not a mistake — it’s a natural and predictable sound change called nasal assimilation (비음화). It happens when a “b/p” sound meets an “n” or “m” sound, because the mouth and tongue adjust to make speech smoother.
Learning this pattern will instantly make your Korean sound more natural and native-like. The next time you say 감사합니다, you’ll know exactly why it sounds like “hamnida” — and you’ll be pronouncing it just like a Korean speaker.