In lossy audio compression, methods of psychoacoustics are used to remove non-audible (or less audible) components of the audio signal. Compression of human speech is often performed with even more specialized techniques; speech coding, or voice coding, is sometimes distinguished as a separate discipline from audio compression. Different audio and speech compression standards are listed under audio coding formats. <answer>Voice compression</answer> is used in internet telephony, for example, audio compression is used for CD ripping and is decoded by the audio players.
What is used in internet telephony? 
Voice compression