Korean Tensification: Lessons and Practice

Key Facts

• After an unreleased ㄱ, ㄷ or ㅂ, the next plain consonant becomes tense: 학교 is [학꾜].
• After a verb stem ending in ㄴ or ㅁ, the ending's first consonant becomes tense: 신고 is [신꼬].
• After ㄹ in Sino-Korean words (words built from Chinese-origin roots), the next consonant becomes tense: 갈등 is [갈뜽].
• After the modifier ending -(으)ㄹ, the next consonant becomes tense: 할 수 is [할쑤].
• In sai-siot compounds, the next consonant becomes tense: 바닷가 is [바다까].
• The tense sound is not shown in Revised Romanization or in the spelling.

Last updated: 2026-10-08. The Korean text, romanization and audio scripts in this section are generated drafts that still await review by a Korean specialist.

What Is Korean Tensification?

Korean tensification is a sound change that makes a consonant tight and short, with no puff of air. A tense consonant is made with a tight throat and a firm release, and it is close to the "p" in English "spin" or the "k" in "sky". The five plain consonants ㄱ, ㄷ, ㅂ, ㅅ and ㅈ each have a tense partner, written as a doubled letter.

Tensification differs from aspiration. An aspirated consonant such as ㅋ has a strong puff of air, while a tense consonant such as ㄲ has none. Both are changes of the same plain consonant, but the trigger decides which one appears. Tensification is also not shown by the spelling, which always keeps the plain letter.

The five triggers differ in how predictable they are. The decision table below sends each situation to one lesson.

Where to Start with Korean Tensification

Start with the overview unless you already know the triggers. The table matches each common situation to one lesson.

A short checklist answers the question "does this word tense?" for the first four triggers.

1. Does a block end in ㄱ, ㄷ or ㅂ (or a letter that sounds like one), and does the next block start with ㄱ, ㄷ, ㅂ, ㅅ or ㅈ? Then it tenses.
2. Is it a verb stem ending in ㄴ or ㅁ, followed by an ending that starts with ㄱ, ㄷ, ㅅ or ㅈ? Then it tenses.
3. Is it a Sino-Korean word with ㄹ before ㄷ, ㅅ or ㅈ? Then it usually tenses.
4. Is it a verb stem plus the modifier ending -(으)ㄹ, followed by a word such as 수, 거 or 데? Then it tenses.

Tensification starts from the final-consonant sounds taught in batchim pronunciation. The most predictable trigger comes first.

What Is the General Rule?

The general rule is that a plain consonant becomes tense after an unreleased ㄱ, ㄷ or ㅂ. These three sounds close the mouth without releasing air, so the consonant that follows is made tight. The rule is fully predictable.

Korean Tensification Rules is the overview lesson. It teaches how to identify the trigger in 학교, 신고, 갈등, 할 수 and 바닷가 and say each with a tense consonant.

Korean Tensification After Batchim covers the unreleased-stop trigger in detail. It teaches 학교, 국밥, 잡다, 옆집, 밥도 and 꽃다발, and shows that the written letters ㅋ, ㅅ, ㅈ, ㅊ, ㅌ and ㅍ also count when they sit at the end of a block.

The next trigger depends on the grammar of the word.

Which Verbs Tense?

Verb stems that end in ㄴ or ㅁ tense the first consonant of the ending. The effect is common, because many everyday verb stems end in ㄴ or ㅁ (including the clusters ㄵ and ㄻ), such as 신다 (wear on the feet), 앉다 (sit) and 닮다 (resemble).

Korean Verb Stem Tensification teaches 신고, 앉다, 삼고, 닮다 and 껴안지. It also teaches the exceptions: the passive and causative verbs 안기다 and 감기다 stay plain, because the ㄱ there belongs to the passive or causative suffix -기-, not to an ending.

Which Words Tense after ㄹ?

Two kinds of words tense after ㄹ: Sino-Korean words and phrases with the modifier ending -(으)ㄹ. Both are common in everyday speech.

Korean Sino-Korean Tensification teaches 갈등, 발달, 일시, 물질 and 발전. Sino-Korean words are Korean words built from Chinese-origin roots. This trigger depends partly on the word, so the lesson gives a list to learn.

Korean ㄹ Ending Tensification teaches 할 수, 갈 거예요, 할 것을, 갈 데 and 먹을 수. The modifier -(으)ㄹ marks an action that has not happened yet, so this is the pattern behind many future-tense phrases.

What about Compounds?

Compounds with a sai-siot, which is an extra ㅅ written between two nouns, also trigger tensification. The extra ㅅ is often not pronounced as ㅅ, but it makes the next consonant tense.

Korean Sai Siot explains when sai-siot is written and teaches 냇가, 바닷가, 콧날 and 나뭇잎 with the right sound change. It sits in the main rules section because the extra ㅅ also affects other rules.

Comparing the Korean Tensification Lessons

The table compares the five lessons by what each fixes and how predictable the trigger is.

Most learners need After Batchim and ㄹ Ending first, because those two patterns appear in the earliest sentences. Each lesson takes about 25 minutes. A short routine then fixes the habit.

How Do You Practise Korean Tensification?

Practise by listening for the tight consonant first, then predicting it from the trigger.

1. Say 학교 as [학꾜] and 국밥 as [국빱].
2. Say 신고 as [신꼬] and 앉다 as [안따].
3. Say 갈등 as [갈뜽] and 일시 as [일씨].
4. Say 할 수 as [할쑤] and 갈 거예요 as [갈꺼예요].

Revised Romanization does not record tensification: 학교 is written hakgyo, so a learner who reads the romanization will say a plain consonant. For the reading rules, see Korean romanization, and for the full set of rules, see Korean pronunciation rules.

Study Order at a Glance

Study the five lessons in this order: Tensification Rules, After Batchim, ㄹ Ending, Verb Stems, Sino-Korean. The first three cover the most frequent words and the last two add the cases that need more word-by-word memory. A learner who completes the first three can predict the tense sounds in most everyday sentences.

Audio, Review Status and Scope

This section covers tensification in Standard Korean. It does not cover aspiration, which makes consonants breathy instead of tense, and it does not cover intonation. All Korean text, romanization and audio are generated drafts that still await review by a Korean specialist, and the audio shows one standard Seoul pronunciation.

Related Sections

Tensification is one of eight rules in the section on Korean pronunciation rules, and it builds on the final consonants taught in batchim pronunciation.

Frequently Asked Questions

What is tensification in Korean? Tensification (된소리되기) is the sound change in which a plain consonant ㄱ, ㄷ, ㅂ, ㅅ or ㅈ becomes its tense partner ㄲ, ㄸ, ㅃ, ㅆ or ㅉ after certain sounds. A tense consonant is tight and has no puff of air. The spelling stays plain, so 학교 is written with ㄱ but spoken [학꾜].

Why is 학교 pronounced 학꾜? The final ㄱ of 학 closes the mouth without releasing air, and a plain consonant after an unreleased ㄱ, ㄷ or ㅂ becomes tense. So the ㄱ of 교 is spoken as ㄲ, giving [학꾜]. Revised Romanization writes hakgyo and does not show the tense sound.

Is tensification predictable? Mostly. The unreleased-stop trigger and the -(으)ㄹ trigger are fully predictable, and the verb-stem trigger is predictable apart from passive and causative verbs such as 안기다. The Sino-Korean trigger and sai-siot compounds depend partly on the individual word, so learners need to memorize those words.

Which cases do beginners meet first? Beginners meet the unreleased-stop case first, in words like 학교, 국밥 and 옆집, and the -(으)ㄹ case in phrases like 할 수 and 갈 거예요. These appear in everyday speech and early lessons. The verb-stem case follows, with 신고 and 앉다, and Sino-Korean words come last.