A three-layered prosody control description language is used to insert prosodic feature control commands in a text at the positions of characters or a character string to be added with non-verbal information. The three-layered prosody control description language is composed of: a semantic layer (S layer) having, as its prosodic feature control commands, control commands each represented by a word indicative of the meaning of non-verbal information; an interpretation layer (I layer) having, as its prosodic feature control commands, control commands which interpret the prosodic feature control commands of the S layer and specify control of prosodic parameters of speech; and a parameter layer (P layer) having prosodic parameters which are objects of control by the prosodic feature control commands of the I layer. The text is converted into a prosodic parameter string through synthesis-by-rule. The prosodic parameters corresponding to characters or character string to be corrected are corrected by the prosodic feature control commands of the I layer, and speech is synthesized from a parameter string containing the corrected prosodic parameters.
Method for editing non-verbal information by adding mental state information to a speech message