Imagine if at some point of the story our MC would be transformed in such way so he will lose ability to speak and AVA will aquare it? Or if it would be somekind of transplantation proccedure of some sort in attempt of MC to make AVA speak.

In wildest dreams it cold lead to situations where AVA can start mock or even dominate MC making him more and more of a drone itself, and only Emilia or some other lab specialist can still be able to understand MC.