Pronunciation2026-06-04 ยท 6 min read

Rendaku (้€ฃๆฟ): Why ๆ‰‹ + ็ด™ Becomes ใฆใŒใฟ, Not ใฆใ‹ใฟ

You know ็ด™ is ใ‹ใฟ (paper). So why is ๆ‰‹็ด™ (letter) read ใฆใŒใฟ? This voicing of the second word in a compound is called rendaku (้€ฃๆฟ). Itโ€™s everywhere, it follows patterns, and it even has a rule for when it stays silent.

JLPT N1 Certified Teacher
Japanese language teacher with experience teaching learners from Vietnam, Indonesia, and Mongolia.

What Rendaku Is

When two words join into a compound, the first sound of the second word often becomes voiced: ใ‹โ†’ใŒ, ใ•โ†’ใ–, ใŸโ†’ใ , ใฏโ†’ใฐ, etc. So ใ‹ใฟ becomes ใŒใฟ, ใฒ becomes ใณ, ใใ‚‰ becomes ใžใ‚‰.

It is not random โ€” it signals โ€œthese two words are now one.โ€ Recognizing it helps you read compounds correctly and understand why a familiar word suddenly sounds different.

Common Examples

ๆ‰‹ + ็ด™โ†’ใฆใŒใฟletter (ใ‹ใฟ โ†’ ใŒใฟ)
ๆ™‚ + ๆ™‚โ†’ใจใใฉใsometimes (ใจใ โ†’ ใฉใ)
่Šฑ + ็ซโ†’ใฏใชใณfireworks (ใฒ โ†’ ใณ)
ๆŠ˜ใ‚Š + ็ด™โ†’ใŠใ‚ŠใŒใฟorigami (ใ‹ใฟ โ†’ ใŒใฟ)
ไบบ + ไบบโ†’ใฒใจใณใจpeople (ใฒใจ โ†’ ใณใจ)
้’ + ็ฉบโ†’ใ‚ใŠใžใ‚‰blue sky (ใใ‚‰ โ†’ ใžใ‚‰)

When It Doesn't Happen (Lyman's Law)

The most useful exception: rendaku is blocked if the second word already contains a voiced consonant (ใŒ, ใ–, ใ , ใฐโ€ฆ). This is known as Lyman's Law.

So ้ขจ (ใ‹ใœ) already has a voiced ใœ โ€” and ๆ˜ฅ้ขจ stays ใฏใ‚‹ใ‹ใœ, not ใฏใ‚‹ใŒใœ. One voiced sound per element is the limit.

How to Handle It

  • Expect it, don't force it. Rendaku is a strong tendency, not an absolute rule โ€” learn each compound as you meet it.
  • Use Lyman's Law as a quick check: if the second word already has ใŒ/ใ–/ใ /ใฐ, it probably won't voice.
  • It connects to spelling: rendaku of ใค/ใก gives ใฅ/ใข (see the yotsugana article).

Teacher's Note

Don't try to predict rendaku perfectly โ€” even native speakers can't for new or rare compounds. Learn the common ones by ear, keep Lyman's Law in your back pocket, and you'll read the vast majority correctly.

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Rendaku (้€ฃๆฟ): Why ๆ‰‹ + ็ด™ Becomes ใฆใŒใฟ, Not ใฆใ‹ใฟ | Nihongo Pass