The inability of a person to alter the sounds of the voice in tone or pitch when speaking: Aprosodias indicate difficulties in expressing the emotional aspects of language (motor aprosodia) and is diagnosed as a non-dominant frontal lobe disease of the brain resulting in a bland, colorless, or blunted (less vigorous) speaking.

There are other kinds of aprosodias that involve inappropriate emotional expressions and the inability to understand the emotional aspects of another person's speech (sensory aprosodia) which suggests damage in the non-dominant temporal area of the brain.