Quite cool... But if this is generated by the text to speech engine from OS X, then I am afraid it is going beyond the license that come up with OS X. I remember reading through that license and it was clearly stated that using the OS X TTS was only for local usage on your Mac. So I am extremely curious to know the license behind this tts-api? Can the OP provide such info or provide some of the tech behind it?
""F. Voices. Subject to the terms and conditions of this License, you may use the system voices included in the Apple Software (“System Voices”) (i) while running the Apple Software and (ii) to create your own original content and projects for your personal, non-commercial use. No other use of the System Voices is permitted by this License, including but not limited to the use, reproduction, display, performance, recording, publishing or redistribution of any of the System Voices in a profit, non-profit, public sharing or commercial context.""