ㄹ → ㄴ After ㅁ, ㅇ (종로 → 종노)

Here is a rule you can literally read off a Seoul street sign — and get wrong. The famous district 종로 is romanized Jongno on the subway map, yet spelled 종로, with a ㄹ. That mismatch is not a typo: when ㄹ begins a syllable right after the nasal batchim ㅁ or ㅇ, it is pronounced [ㄴ]. So 종로 is [종노], 정류장 ("bus stop") is [정뉴장], and 대통령 ("president") is [대통녕]. This is a close partner of the stop-before-nasal rule: there a stop caught nasality from a following nasal; here a liquid catches it from a preceding one.

The rule in one line

An initial ㄹ is said [ㄴ] after a syllable that ends in the nasal ㅁ or ㅇ. The ㄹ takes on the nasality of the coda in front of it.

종로 → [종노]: the ㄹ of 로, sitting after the ㅇ of 종, is pronounced [ㄴ].

정류장 → [정뉴장]: the ㄹ of 류 becomes [ㄴ] after the ㅇ of 정 — so you hear [뉴], not [류].

Why it happens: ㄹ won't stand after a nasal

Korean ㄹ is a liquid — a flap [ɾ] between vowels, a lateral [l] as a coda. Sequencing a nasal directly into a liquid ([ŋ] → [l], [m] → [l]) is awkward for the language, so the ㄹ assimilates the [+nasal] feature of the consonant before it and surfaces as [ㄴ], the nasal made at the very place ㄹ already lives (the alveolar ridge). Nothing else moves; the liquid just picks up nasality from its left-hand neighbor.

This is the mirror image of lateralization, the rule you meet next. There, ㄹ is the stronger sound and pulls a neighboring ㄴ toward itself (신라 → [실라]). Here, a nasal coda is dominant and pulls the ㄹ the other way, into [ㄴ]. Same two letters, opposite winner — and which one wins depends entirely on what the ㄹ is standing next to. After ㅁ/ㅇ, the nasal wins and you get [ㄴ]; after ㄴ or another ㄹ, the liquid wins and you get [ㄹㄹ].

종류 → [종뉴] (ㄹ → [ㄴ] after ㅇ). 많아요 links to [마나요].

It's almost always a Sino-Korean word

There's a reason nearly every example here is a two-part Chinese-derived compound. Korean has a "head-sound rule" (두음법칙) that bans an initial ㄹ at the start of a Sino-Korean word: 로동 is written and said 노동 ("labor"), 리유 becomes 이유 ("reason"). But inside a compound, a morpheme like 로(路), 료(料), 리(理), 력(力), or 령(領) keeps its original ㄹ in the spelling — and then this pronunciation rule nasalizes it to [ㄴ] whenever the preceding morpheme ends in ㅁ or ㅇ.

So the spelling faithfully records the Sino root (종 + 로), while your mouth applies the rule on the way out ([종노]). Once you know the trigger, you can predict it in words you've never seen: any 심-, 종-, 정-, 대통-, 능- syllable followed by a 로/료/리/력/령 will do it.

대통령 → [대통녕]: the ㄹ of 령 becomes [ㄴ] after the ㅇ of 통.

음료수 → [음뇨수]: here the trigger is the ㅁ of 음, and the ㄹ of 료 becomes [ㄴ] → [뇨].

After ㅁ and after ㅇ — a few more you'll actually use

능력 → [능녁] (ㄹ → [ㄴ] after ㅇ); with the particle 이 it links to [능녀기].

심리 → [심니] (ㄹ → [ㄴ] after ㅁ). The same rule gives 명령 → [명녕] ("order"), 침략 → [침냑] ("invasion"), and the place name 강릉 → [강능].

등록 → [등녹] (ㄹ → [ㄴ] after ㅇ); with 은 it becomes [등노근].

The boundary just ahead: after a stop it's a two-step chain

This page is only about ㄹ after a nasal (ㅁ, ㅇ), where a single change happens. But the very same distaste for "consonant + ㄹ" fires after a stop batchim (ㄱ, ㅂ) too — and there it triggers a chain: the ㄹ becomes [ㄴ], and then that fresh [ㄴ] nasalizes the stop in front of it. That is why 국립 is not [국닙] but [궁닙], two rules deep. Keep it separate in your head for now; the full treatment is on the double nasalization page.

국립 → [궁닙] — notice the ㄱ also changed. That extra step is what the chain page is about; after ㅁ/ㅇ (this page), only the ㄹ moves.

Common Mistakes

1. Reading the ㄹ as [ㄹ] after ㅁ or ㅇ. 종로 is [종노], not [종로]; 심리 is [심니], not [심리].

2. Saying [류] instead of [뉴] in everyday words. 정류장 → [정뉴장], 종류 → [종뉴].

3. Rolling or trilling the ㄹ here. Even where ㄹ is pronounced, Korean has no Spanish-style trill — and in this environment there's no ㄹ sound at all. It is a plain [ㄴ]. Say 대통령 as [대통녕].

4. Over-generalizing to every ㄹ. The change is triggered specifically by a preceding ㅁ or ㅇ. After a vowel, ㄹ stays a liquid (음료 has it, but 자료 → [자료], 재료 → [재료] keep [ㄹ] because the syllable before ends in a vowel).

Key Takeaways

• An initial ㄹ becomes [ㄴ] after the nasal batchim ㅁ or ㅇ: 종로 [종노], 정류장 [정뉴장], 대통령 [대통녕], 심리 [심니].
• It happens because ㄹ won't sit right after a nasal — the liquid catches the [+nasal] feature and surfaces as [ㄴ]. This is the mirror of lateralization, where ㄹ instead wins.
• It's overwhelmingly a Sino-Korean phenomenon: the head-sound rule keeps ㄹ out of word-initial position, but an internal 로/료/리/력/령 keeps its ㄹ in spelling and nasalizes in speech.
• After a stop (ㄱ, ㅂ) the same ㄹ triggers a two-step chain (국립 → [궁닙]); after ㅁ/ㅇ only the ㄹ moves.
• Trust the Hangul rule over familiar romanizations — 종로 the sign says "Jongno," and that is the sound: [종노].