In this paper, we propose a communication support tool for understanding emotion in an unstable narrowband network. The tool can support mutual understanding when playing a selected voice by using also a character-based communication tool. The voice data is transmitted asynchronously and stored in local storage. Our proposed tool has been evaluated by a questionnaire survey after using some web-based voice contents classified according to some massage types and primitive emotion. From the questionnaire survey results, we discuss the effectiveness of emotional voice message when displaying text message.