An apparatus and method for detecting and controlling audible errors in a sound
communication system at the receiver utilizes channel quality data and also iterative
synthesis. Errors occurring in synthesized speech are detected by searching for
atypical sound with a stringency dependent upon channel quality. The greater the
channel quality deficiency is, the higher the typicality standards will be. Errors
are controlled by either re-synthesizing the signal in an iterative way using typicality
standards which vary with channel quality deficiency, or by modifying the output
signal using typicality standards which vary with channel quality deficiency, or both.