You know how in fantasy worlds, its all english? Kinda breaks the immersion a bit. I wanna find something where they make it as realistic as possible, and make everything in a fictional language, basically using subtitles as the main way to understand the plot.
As far as video games go, an obvious answer is the Sims.
Perhaps only slightly less prominent is Shadow of the Colossus. Insofar as I know all of the spoken dialog is a nonsense fictional dialect that definitely isn’t Japanese, except possibly when calling your horse’s name. The language is based off of syllables and random bits from both Japanese and Latin with some of the syllables being spoken backwards, and with a kinda-sorta Japanese style cadence. But it’s utter gibberish, and only the subtitles make it intelligible.
I think Ico and Last Guardian from the same company use the same language