1. N igori . There is a widespread and largely unsystematic type of alternation which is often called nigori (Japanese: niŋorí 'voicing'). The term nigori, however, has been applied to a variety of different phenomena: a historical development, a class of phonemes, an orthographic marker indicating members of this class, and a type of morphophonemic alternation. Since the term would be relevant to the present discussion only in the last sense, it seems preferable to use the less ambiguous expression voicing alternations . The Japanese terms dakuon̄ Voiced member of a voiced–voiceless pair of phonemes' and ren̄daku ‘sequential voicing alternation’ are more specific than niŋorí, but these are also subject to ambiguous use.
A Mon, study studied this question.