Abstract: A messaging application supports a mode of communication in which users can add audio effects to text messages in order to express emotions. These audio effects are described as audiocons. The audiocons may also alternatively include visual effects. In one implementation the message application supports system-defined audiocons, user-defined audiocons, and text-to-speech audiocons. Additionally, the audiocons may be inserted into a communication stream having a mixture of calls, text messaging, and instant messaging including a system having a real-time mode for time-based media and a time-shifted mode.