I have some fragmentary memories of a sci-fi library my father had, and I would really like to find some of those books. Having just bits and scraps of memories doesn't help with search, but a few of them should be enough to pinpoint the book in question.
So - those were Russian translations published in the 90s.
Let's try this one: a novel, in which there was a supercomputer which communicated via/with a special caste of people that learned to talk in its insanely complex verbal language.
It also had Matrix-like VR it could put people to, in sensory isolation pods. The protagonist, as he was training to speak this language, was put into that VR. And the computer made the VR respond to how well the person could intone the language, with (unattainable) perfection being rewarded with a carrot-on-a-stick of a cold drink on a paradise-like beach.
If I'm not mixing things up, the protagonist was undergoing this training as an alternative to being recycled for organs, as he was (unjustly, I think) accused of some crime punishable by this "rational" form of death sentence. There was a sanatorium where such sentenced people were living, and were slowly, piece-by-piece used as transplant material as need arose. I remember one of the characters having a black-skinned hand from such a convict on an otherwise white body. If I am mixing things up, this is a separate novel I'm also interested in.