4. key words: tone, tone recognition, F0 contour, average F0 contour The program can be separated into 2 parts, Thai tone practicing for common persons (especially the foreigners) and Thai tone practicing for the hearing deficient persons. The program uses the tone recognition for checking the users’ utterances. When the voice of a program user is inputted, the fundamental frequency of the voice will be analyzed by the program. Then, the program will calculate the coefficients in the polynomial equations that fit the F0 contour. After we have the coefficients in matrix [B], the program will calculate the standard deviation, Baverage and Z-score of [B]. Outputs of the program are the user’s F0 contour compared with the average F0 model, tonal accuracy and degree of loudness.