sibilants

In speech production, sibilants are a subset of fricatives characterized by loud, high-pitched sound. In English the sibilant sounds are /sssssssss/, /zzzzzzzzz/, /ʃshshʃshshʃshsh/, /ʒzhzhʒzhzhʒzhzh/, /tttttttttʃshshʃshshʃshsh/, /dddddddddʒzhzhʒzhzhʒzhzh/.