Under nasal mutation, voiced stop consonants become nasals, and unvoiced stops become voiceless nasals. Modern Greek consonants are plain (voiceless unaspirated) stops, voiced stops, or voiced and unvoiced fricatives. The fricative and its unvoiced counterpart are rare phonemes. The Tamil script does not differentiate voiced and unvoiced plosives. Under aspirate mutation (), unvoiced stops become fricatives. There is no voiced consonant with an unvoiced counterpart, nor vice versa. In addition to voiced and unvoiced consonants, there are also ejectives. "unvoiced" in Tocharian and Anatolian and aspirates (later fricatives) in Greek and Italic. Speech sounds can be described as either voiceless (otherwise known as "unvoiced") or voiced. It makes extensive use of fricatives, both unvoiced () and voiced (. Voicing is what separates English in "bus" (unvoiced sibilant) from in "buzz" (voiced sibilant). The opposite type of anticipatory assimilation happens to voiced obstruents before unvoiced ones&colon; . Old English used "S" alone for both the unvoiced and the voiced sibilant. It is voiced, its unvoiced counterpart being . Often there is an unvoiced band or sibilance channel.