Let's not forget that the human brain is already a Universal Translator. It takes gibberish for input and creates interpretations for output. Sometimes those happen to be correct interpretations; most often not. But the brain's one forte is self-deception: garbage in, wonderful truths out is what it was built for, and it achieves that by smoothing out the edges.
Terhe aer pelnyt of cloo emplaxse of tihs. Say, it didn't take your brain half a second of extra time to ignore the incorrect ordering of letters in that sentence; ignorance is the real human superpower.
The UT could easily exploit that. It wouldn't take much tickling of the brain to make us see the opponent's lips move in synch with what our ears are telling us (hell, we can do that
without implanted brain-ticklers today!), nor to make us hear perfectly understandable phrases when alien speech hits our ears, an implant translates about 75% of it very coarsely on the way to the brain, and finally the brain does its usual ignoring on the input and spits out some understanding.
Let me ask you to elaborate a bit more on this. It seems that you are suggesting that in addition to its basic function, the UT is also able to draw on some dataset that has archived a representation of how the articulation of the user's native language should visually appear when rendered, and is able to simultaneously track and then overlay this sensory input alongside the translated speech. If so, would you draw a distinction in these two capabilities?
I am not sure that in both instances one would necessarily say that the user's perceptions are being changed. As far as the translation piece, the individual is not actually hearing anything other than what their interlocutor(s) are actually saying, putting to the side any "extreme" idiomatic, syntactical or other constructions that are beyond the UT's capability to effectively discern. However seamlessly and without appreciable delay it is made available to the user, this output has presumably not been altered from how it is actually presented, including of course being heard in the other person's voice rather than a synthesized recreation. This does not seem different in substance than a super realized version of an old school Mission Impossible style gewgaw that might have portrayed a running instantaneous translation capability piped in through a cleverly hidden earpiece.
The appearance of articulation that is compatible and actually synonymous with the user's expectations does however represent an objective difference in the manifestation of the other's expression. This would seem to me to represent a material difference in the UT's operational capability. This requires an action being produced that allows either individual to see something that is not really present and presumably would not be captured by an independent view that is not also utilizing the same technology.
Am i barking up the wrong tree, going around the bend, etc. If so, perhaps I might be best advised to reevaluate my suitability to contribute to this august forum even though its still early days!