We use splitting of the digital stream for stream encryption with the Vernam code. How to make it harder or impossible to hack a stream. Engineering solutions. Let's write sample applications for Android Java.
Speech technology in encryption is not speech encryption.
Well and then it is possible to consider enciphering on the basis of "other thinking". For example, based on huge programming objects. This encryption is likely to be stable even during quantum computers.
Then we'll come up with something else