Two types of voice can be set for reading text data of an electronic mail. A user selects a detailed setting button associated with one of the voice types to display a voice setting window, in which setting for the voice can be made individually. A drop-down list box include preset voice types such as woman, man, child, robot, and alien, and also names of voice types corresponding to phonemes created by the user, allowing selection thereof. In relation to a voice selected from the drop-down list box, reading speed, voice pitch, and strength of stress are set according to positions of setting levers.