Tensification (경음화)
After stop consonants ㄱ, ㄷ, ㅂ, plain consonants ㄱ/ㄷ/ㅂ/ㅅ/ㅈ become tense (된소리).
Tensification (경음화) is the rule that turns plain consonants into their tense counterparts in specific environments. The main trigger is when the previous syllable ends in one of the 'stop' final consonants ㄱ, ㄷ, or ㅂ. Following the stop, any plain ㄱ / ㄷ / ㅂ / ㅅ / ㅈ becomes tense: ㄲ / ㄸ / ㅃ / ㅆ / ㅉ.
Example: 학교 (school) is spelled hak + gyo but pronounced hak + kkyo. The ㄱ at the end of 학 triggers tensification on the next ㄱ. Native speakers do this automatically and do not consciously notice the change, but for learners it is one of the gaps between 'reading speed' and 'listening speed'. After enough exposure, you will start producing tense consonants automatically when speaking — at which point your Korean will sound noticeably more native.
경음화 — Tensification Rule
When a syllable ends in ㄱ, ㄷ, or ㅂ (unreleased stop), the following consonant ㄱ/ㄷ/ㅂ/ㅅ/ㅈ becomes its tense counterpart: ㄲ/ㄸ/ㅃ/ㅆ/ㅉ. This makes the sound feel more 'tight' or 'sharp'.
경음화 — Common Patterns to Remember
경음화 is very common in compound nouns, place names, and everyday words. Once you recognize the pattern, you'll hear it everywhere: 입구[입꾸], 국밥[국빱], 합격[합껵].
How It Works
경음화 follows directly from how final stops are pronounced. When a syllable ends in ㄱ, ㄷ or ㅂ, the mouth closes and holds — the consonant is never released. That held closure builds pressure and leaves the vocal tract tensed. If the next syllable begins with a plain consonant, it inherits that tension and comes out tense instead: ㄱ→ㄲ, ㄷ→ㄸ, ㅂ→ㅃ, ㅅ→ㅆ, ㅈ→ㅉ.
So 학교 is written with a plain ㄱ but spoken [학꾜], because the unreleased ㄱ of 학 leaves no room for a relaxed consonant to follow. 식당 becomes [식땅] for the same reason. The spelling stays plain because the underlying consonant is plain; the tensing is a predictable consequence of position, not a different word.
This is worth contrasting with 연음화 from the previous lesson, because the two rules are triggered by opposite conditions. If the next syllable starts with a vowel (ㅇ), the 받침 moves forward and is released — 먹어요 → [머거요]. If the next syllable starts with a plain consonant, the 받침 stays put and tenses what follows — 먹다 → [먹따]. Same 받침, same word stem, two different outcomes decided entirely by what comes next.
Where You'll Hear It
경음화 is extremely common in compound nouns, which is where two words are pushed together and a final stop meets an initial plain consonant. 학교 ('school'), 식당 ('restaurant'), 국밥 ('rice soup'), 입구 ('entrance'), 박수 ('applause'), 합격 ('passing an exam') are all everyday words that are never pronounced the way they are spelled.
Place names and signage are dense with it. Station names, building directories and shop signs constantly produce this environment, so a learner reading aloud from a sign will sound noticeably non-native if they use plain consonants throughout.
It also affects basic grammar. The dictionary form of every verb ends in -다, so any verb stem ending in ㄱ, ㄷ or ㅂ triggers tensing: 먹다 is [먹따], 입다 is [입따], 닫다 is [닫따]. Since this is how verbs are listed in dictionaries and taught in classes, learners encounter the pattern from their very first vocabulary list — usually without being told that the pronunciation differs from the spelling.
Cultural & Language Note
경음화 explains a puzzle beginners notice early: why does 학교 sound like 'hakkyo' when it is spelled with a plain ㄱ? Because a stop consonant in 받침 position tenses whatever follows. Koreans are largely unaware they do this. If you ask a native speaker how 학교 is pronounced, many will say 'hak-gyo' — describing the spelling, not their own speech.
Common Mistakes to Avoid
The mistake is not applying it — pronouncing 식당 as 'sik-dang' instead of 'sik-ttang' marks you instantly as a learner. The rule is automatic after ㄱ, ㄷ, ㅂ 받침, so build the habit at the word level rather than computing it each time. Note that 경음화 also occurs in some compound nouns without a stop 받침 at all, and those simply have to be learned individually.
How to Practice This Lesson
Do not memorise a word list of exceptions, because these are not exceptions — the rule is regular. Instead, learn to spot the environment: a ㄱ/ㄷ/ㅂ 받침 immediately followed by ㄱ/ㄷ/ㅂ/ㅅ/ㅈ. Scan any Korean text for that pattern and mark every instance you find. Ten minutes of spotting builds the reflex faster than any amount of rote learning.
Then practise the contrast with 연음화 explicitly, since the two rules compete. Take one stem and run it both ways: 먹어요 [머거요] versus 먹다 [먹따]; 입어요 [이버요] versus 입다 [입따]. Saying the pair out loud makes the conditioning obvious — vowel after, consonant moves; consonant after, consonant tenses.