A unified communications system includes an SMS command processor configured for executing prescribed messaging operations based on reception of an SMS message having respective prescribed commands, and a text-to-speech resource configured for controlling conversion of the SMS message into an audible message. The SMS command processor parses the received SMS message for the prescribed command, and executes the prescribed command as necessary. In response to detecting a text-to-speech command, the SMS command processor invokes the text-to-speech resource for conversion of the SMS message into an audible message. The SMS command processor outputs the audible message for delivery of the audible message, for example using a notification service that initiates an outgoing telephone call to a messaging destination specified in the SMS message, or by establishing a voice over IP telephone connection with the messaging destination and playing the audible message.