SonoFlex is by default sending text to the message window and speaks all text when pressing the text window. If you are using SonoFlex for iOs, this is possible to change as of version 1.1. Just go to general settings - SonoFlex. It is not possible in SonoFlex for Android though.
SonoFlex for Tobii Communicator gives you full flexibility to customize button and text message window behavior.