mus·si·ta·tion /ˌməsəˈteʃən/ 名詞
  無聲囁語
  Mus·si·ta·tion n.  A speaking in a low tone; mumbling. [Obs.]
  ◄ ►
  mussitation
       n : a low continuous indistinct sound; often accompanied by
           movement of the lips without the production of articulate
           speech [syn: mutter, muttering, murmur, murmuring,
            murmuration]