Yeah, such a protagonist is the best bet. And if at E3, maybe just tidbits.
It is set in an open world metropolis called Night City, whose inhabitants communicate in non-English languages. Players who do not speak the languages can buy translator implants to better comprehend them; depending on the advancement of the implants, the quality of translations will vary, with more expensive implants rendering more accurate translations.
Hmm. Not too many games have "that", meaning alternative, unique dialogue.
I believe the most extensive ones are Arcanum (Intelligence 5+ vs <5) and VTM Bloodlines (the "insane" Malkavian clan - very different from the rest of the clans). Both were made by ex- Fallout 1 & 2 devs*, as *Obsidian kind of carried on in New Vegas. Altho the others relevantly scale a bit and have good moments, VTMB is arguably best with (much) more dialogue that, while less reactive or consequential, has cleverer exposition and better acting. I'm unaware of other games as extensive (well, except this, lol). Bioware attempted dumbspeak in NWN1 but it's only our character's text, no responses from any NPCs AFAIK, and they ditched it in the expansions. Obsidian didn't do it in NWN2, tho decently a few years later (not on F1&2's levels, yet closer to them than F3; F2's is the best of those, and Arcanum is a notch or two above F2, IIRC). (Edit: This paragraph is sloppy, as it's been several years since I played some of them, and my struggle/laziness to find good comparison vids.)
Put such stuff with a different class/style, good C&C, etc., and I got me another great playthrough. I'm not forgetting the rest, like the Nosferatu clan's ugliness (which NPCs react to), Silver Shroud, or
Overseer First Citizen Lynette's dialogue mechanics - the latter mentioned by a CDPR guy in an old article I failed to dig up. And I realise this feature could be very different, possibly even better. Instead of real languages, maybe CDPR would use and expand Witcher's semi-fake languages? Also possible that development might be stretched, making this too shallow (less interaction, more background fluff), it could be a logistical nightmare or a feature they simply don't want, so I shouldn't get hyped...