Methods, computer program products, and systems are presented. The methods include, for instance: a voice delivery application, running on a mobile device of a user, receives a text message from a user; by use of sensor inputs of the mobile device, the mobile device stores data regarding environment of the mobile device including external audio equipment, speed of the user, and bystanders within a hearing range of the environment; various data describing a sender of the text message and the bystanders are analyzed for respective relationships with the user and with each other to determine a confidentiality group dictating whether or not the text message may be heard by the bystander; the text message may be scanned for content screening, then according to configuration of the voice delivery application, the text message is securely delivered to the user by voice.