In this case the AI voices are reading the exact copyrighted material so the original author or rights holder must be contacted to secure the necessary rights and licensing agreements. There is no free use argument.
Now, if the voices have been trained on copy protected sources to create a likenesses (e.g. Scarlet Johansson) then there could be a lawsuit.
AI voices are not trained on books.
The ethical issue there is more around cloning celebrities
https://open.spotify.com/show/03fNX9EtXbfyVzR4z122Ir
but AI itself is
Not sure what you are trying to say here. AI itself is an equation.
AI models have been trained on copyright protected books illegally. Maybe the voice have not
In this case the AI voices are reading the exact copyrighted material so the original author or rights holder must be contacted to secure the necessary rights and licensing agreements. There is no free use argument.
Now, if the voices have been trained on copy protected sources to create a likenesses (e.g. Scarlet Johansson) then there could be a lawsuit.