The "AI-generated dialogue" is any dialogue generated live during play using artificial intelligence, such as GPT-4. If the developers of a game say that their scripts were co-written or fully written with AI beforehand, this would not count. Mods do not count, only the game as released by the developers.
To make verification easy for whether a game is "critically acclaimed" I will check Wikipedia's section for 2026 games that won awards at awards shows or achieved high scores from Metacritic (i.e. 90+).
See also:
@SantiagoRomeroBrufau If multiplayer bots produce "AI-generated dialogue", are in a game that is "critically acclaimed" and "as released by the developers", and then I'd be inclined to count that as a YES, even if the bots were only accessible if the customer pays for a separate subscription on top of the main game purchase.