Japanese IPA transcription maps kana morae to International Phonetic Alphabet symbols. Because the kana scripts are syllabic, transcription is largely a lookup table, but several productive rules — yōon palatalization, the geminate sokuon, long vowels, and the moraic nasal — must be resolved from surrounding context.
Who uses Japanese IPA transcription?
Linguists cite Japanese in comparative phonology papers and need a consistent notation. Language teachers and textbook authors use IPA to explain Japanese pronunciation to speakers of other languages, especially for sounds that have no near-equivalent in English. Voice-over artists recording Japanese text, or phoneticians comparing accent patterns across dialects, also rely on IPA as a shared reference frame that is independent of any one writing system. This tool converts kana directly to IPA without requiring the user to have specialist linguistic training.
How it works
The transcriber normalises katakana to hiragana, then walks the string mora by mora using a lookup table built on modern standard Tokyo Japanese phonetic values:
う-row vowel → /ɯ/ (す /sɯ/, つ /tsɯ/, ふ /ɸɯ/)
し / ち / じ → /ɕi/ /tɕi/ /(d)ʑi/
small ゃゅょ (yōon) → palatalize previous onset: きゃ /kʲa/, しゃ /ɕa/
small っ (sokuon) → geminate next consonant: っか /kka/, っぱ /ppa/
ー or vowel doubling → long vowel: おう→/oː/, えい→/eː/
ん (moraic nasal) → /ɴ/Each mora is appended in sequence; the geminate and yōon rules look one mora ahead or behind to combine with the adjacent onset.
The phonological details that matter
The う vowel is /ɯ/, not /u/. English speakers hear Japanese u as similar to the /u/ in “rule”, but Tokyo Japanese has a high back unrounded (or compressed) vowel that IPA writes /ɯ/. This distinction matters whenever the transcription is used to teach or compare sounds cross-linguistically.
Yōon contractions. When a small ゃ, ゅ, or よ follows a consonant kana, the pair contracts into a single mora with a palatalized or affricate onset. にゃ is not /ni/ + /ja/ but the single unit /nʲa/; ちゃ is /tɕa/, and じゃ is /(d)ʑa/. The tool handles all standard yōon pairs.
The moraic nasal. The kana ん is a mora in its own right — it has the same timing weight as any vowel mora, which is why しんぶん (shinbun, newspaper) is four morae even though there are no vowels in the ん position. Its IPA symbol /ɴ/ is the underlying form; in running speech it assimilates to the following consonant’s place, but the tool outputs the broad phonemic form.
Worked examples
| Japanese | Gloss | IPA |
|---|---|---|
| がっこう | school | /ɡakkoː/ |
| しんぶん | newspaper | /ɕiɴbɯɴ/ |
| きゃく | guest | /kʲakɯ/ |
| ふじさん | Mt Fuji | /ɸɯʑisaɴ/ |
がっこう shows two rules at once: the small っ geminates /k/ to /kk/, and the おう sequence yields the long /oː/. ふじさん shows the labial fricative /ɸ/ for ふ and the moraic nasal at the end.
This output is a broad phonemic transcription. Allophonic variation — nasal assimilation, vowel devoicing between voiceless consonants, pitch accent — is deliberately absent. For narrow phonetic transcription or pitch-accent notation you would need dialect-specific data beyond what kana alone encodes.