In this radio portable terminal communication system, a service document file is converted into a window-related document file, speech-dialog-related document file, and information sharing document file. A description of a telephone number for speech communication with a center is added to the window-related document file. The window-related document file is output to a place where the file can be used through packet communication. The speech-dialog-related document file is output to a place where the file can be referred to by a speech dialog control section (207). The information sharing document file is output to an information management section (204). The information management section (204) manages information in accordance with the general-purpose description language contents of the information sharing document file such that information can be shared between the window-related document file and the speech-dialog-related document file. Since information about windows and speech dialog is created by using a general-purpose description language in this system, the number of steps in development can be reduced.