Middle Japanese Phonology

The system represented by the spelling of Late Old Japanese essentially continued with little significant change until modern times, and it is, therefore, not usual to transcribe Middle Japanese (MdJ) as if it were pronounced differently from Late Old Japanese. However, pronunciation changed significantly, and romanised works produced by Portuguese missionaries in the late sixteenth and early seventeenth centuries show how later MdJ was pronounced. The romanisations used by the Portuguese show the following basic differences:


  • Before i (and y), LOJ t and d were now pronounced like English ‘ch’ and ‘j’ (Portuguese transcriptions: chi and ggi).
  • Before e and i (and y), LOJ s and z were now pronounced like English ‘sh’ and the ‘s’ in measure (Portuguese transcriptions: xe, xi and je, ji).
  • Before u, LOJ t and d were now pronounced like ‘ts’ and ‘dz’ (Portuguese transcription: tçu and zzu).


  • Sequences of vowel + u, either in words of Chinese origin or in native words that had lost an older f or w, had been simplified to long vowels:


MdJ Portuguese Romanisation
au ó
ou ô
uu û
eu yo
iu yu

This meant that, alongside the five short vowels a, e, i, o, u, MdJ also had the long vowels ó, ô, and û. The difference between ó and ô was the same as between Modern French mort and mot or, more roughly, English ought and oat.

If you have any questions about Middle Japanese phonology, please email Dr. Nic Tranter.

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