Tense After ㄹ in Sino-Korean Words (발달 → 발딸)

The after-stop tensification is beautifully automatic: any stop batchim tenses whatever plain consonant follows, no exceptions. This page covers a second tensification that is much more restricted — it fires after a batchim ㄹ, which is not a stop at all, and only inside Sino-Korean (한자어) vocabulary, and only for three target consonants. Because ㄹ is a sonorant (it builds no oral closure), there is no physical priming to lean on the way there is after a stop; this pattern has to be learned as a property of the Sino-Korean lexical layer. It is codified in Korea's standard pronunciation rules (표준발음법 제26항), and it is worth mastering because these words — 결정, 발전, 갈등, 절대 — are everywhere in intermediate Korean.

The rule: ㄹ + ㄷ/ㅅ/ㅈ → ㄸ/ㅆ/ㅉ

In a Sino-Korean word, when a batchim ㄹ is followed by ㄷ, ㅅ, or ㅈ, that consonant tenses.

발달 is 발[l] + 달, and the ㄷ tenses to ㄸ: [발딸]. 갈등 is 갈[l] + 등, ㄷ → ㄸ: [갈뜽]. 절대 is 절[l] + 대, ㄷ → ㄸ: [절때]. The same happens with ㅅ and ㅈ targets:

Why only three consonants — and why ㄱ and ㅂ escape

Here is the piece that turns a memorized list into a pattern. The three consonants that tense — ㄷ, ㅅ, ㅈ — are all coronal: they are articulated with the tongue tip or blade at the alveolar ridge, in the same front region of the mouth as ㄹ itself. The two that don't tense — ㄱ (velar) and ㅂ (labial) — are made elsewhere: ㄱ at the back with the tongue body, ㅂ at the lips. So the tensing after ㄹ is confined to consonants that share ㄹ's place region. This is why 결과 (result) stays [결과] and never [결꽈], and 일부 (a part) stays [일부] and never and ㅂ are simply outside the rule.

Why only Sino-Korean words

The restriction to the Sino-Korean stratum is the trickiest part, and it is genuinely lexical — there is no way to hear from the sounds alone that a word is 한자어. You develop a feel for it: two-syllable abstract nouns built from Chinese-derived roots (발전 "development," 결정 "decision," 열정 "passion," 갈등 "conflict," 절대 "absolute") almost all belong to this layer, and they take the tensing. Native-Korean words with a ㄹ batchim generally do not follow this exact rule — instead they fall under the separate compound and 사이시옷 tensification, or take no tensing at all. For background on telling the two vocabulary layers apart, see Sino-Korean vs. native words.

Be honest with yourself about the limits of the rule: because it is codified per word rather than fully productive, a dictionary check is the final authority. The standard-pronunciation entries in a good Korean dictionary mark the tensing in brackets, and when your ear and the rule disagree, trust the dictionary.

It is a different mechanism from the after-stop rule

It is worth stating plainly why this needs its own page instead of folding into the automatic rule. After a stop batchim, tensing is phonetic and exceptionless — the held closure primes the tract, and everything tenses, in any word, native or Sino, always. After ㄹ, there is no closure to prime anything, so nothing is automatic; the tensing is a lexical convention limited to Sino-Korean words and to the coronal set ㄷ/ㅅ/ㅈ. Same audible result (a tense consonant), completely different cause. Keeping them separate is what lets you predict 발달 → [발딸] but also correctly not tense a superficially similar native phrase.

A quick reference set

These high-frequency Sino-Korean words all tense after ㄹ. Reading them aloud a few times builds the reflex faster than any rule.

And the escapees — ㄱ and ㅂ, which stay plain: 결과 [결과], 결국 [결국] (in the end), 일부 [일부], 활보 [활보] (striding, formal). Never tense these.

Common Mistakes

1. Failing to tense the coronal set. Saying the ㄷ/ㅅ/ㅈ plainly makes the word sound un-Korean.

• ✗ 발달 said [발달] → ✓ [발딸]
• ✗ 결정 said [결정] → ✓ [결쩡]

2. Over-generalizing and tensing ㄱ or ㅂ too. The rule stops at the coronal three.

• ✗ 결과 said [결꽈] → ✓ [결과]
• ✗ 일부 said [일뿌] → ✓ [일부]

3. Applying the rule to native-Korean words by analogy. This pattern belongs to the Sino-Korean layer; native ㄹ words follow the compound rule or none at all.

4. Confusing it with after-stop tensing and expecting it to be automatic. After ㄹ there is no closure priming anything — the tensing is lexical, so verify unfamiliar words in a dictionary rather than assuming.

5. Reading the romanization as the target. Like all tensing, this change is not shown in Revised Romanization — 발달 is baldal, not balttal. The bracket [발딸] is where the truth lives.

Key Takeaways

• In Sino-Korean words only, a batchim ㄹ tenses a following ㄷ, ㅅ, ㅈ → ㄸ, ㅆ, ㅉ: 발달 [발딸], 결정 [결쩡], 일시 [일씨].
• ㄱ and ㅂ do not tense after ㄹ — they are made outside ㄹ's coronal region: 결과 [결과], 일부 [일부].
• This is a lexical rule tied to the Sino-Korean stratum, not the automatic phonetic tensing you get after a stop batchim.
• Revised Romanization never marks it (baldal), so read the bracketed 발음, and check a dictionary for unfamiliar 한자어.