When foreign words or proper names are used in Japanese, some modifications are necessary, in particular a lot of vowels are introduced. E.g. 'plastic' (two syllables) becomes プラスチック (five). In this case, it is not that the three /u/ will turn out to be unvoiced: this vowel was chosen precisely to yield a pronunciation not too different from 'plastic' -- it is unvoiced by design so to speak.

So are there either formal rules or a tendency to silence these vowels to be as close as possible to the original? Or is there no special status?

  • 1
    Usually only the vowel in ス is devoiced.
    – user1478
    Feb 12, 2019 at 12:17
  • Doesn't the ッ in プラスチック count?
    – BJCUAI
    Feb 12, 2019 at 19:30

2 Answers 2


The devoicing of vowels in Japanese is determined by the internal phonological environment of Japanese words. There is a relatively small set of circumstances under which it happens, e.g. the vowels 'i' and 'u' are often devoiced between two voiceless consonants (くつ) or following a voiceless consonant at the end of a word (です). With such limited scope under which devoicing is possible, it is very unlikely that this plays any significant role in the decisions about kana choice for loanwords. There are simply not enough conditions at play to manipulate the word in an attempt to preserve its original phonemic expression. Other factors are more likely to play a decisive role.

It is certainly an interesting area and there are some threads on the site which discuss the factors which might influence the choice of kana. I think you will find them of interest. See below:


You have several other syllables that can be unvoiced for pronunciation reasons like キ or ト. The perfect example would be the word for Christianity which is キリスト教 (pronounced きりすときょう). Here, the 「キ」 corresponds to the 'Ch' so the 'i' is unvoiced. The same goes for 「ト」which corresponds to the 't' in 'Christ'.

Loanwords use the Japanese syllabary so you can't put a consonant alone: you have to use another syllable whose vowel can be unvoiced. As a general tendency, syllables ending with 'u' have got it unvoiced. For the た行, you should use 「ト」 and not 「ツ」 (e.g. トラウマ, trauma) and, where the か行 is concerned, 「ク」is the most used one, but 「キ」can be used sometimes (as you can see in the first example).

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .