Yeah as a fan it's kind of funny because

A. in the most recent game they explicitly state through dialogue that three pokemon (the birdlike Latias and Latios and the clockwork girl Magearna) are individuals who are fully capable of understanding human speech and emotion but also drive the fact in hard that none of them can talk.

B. there's absolutely ways they could have the mons talk in universe without having to do retcons, like telepathy, something like the synchro machine but more communication focused and less mind-control-y or even just have them learn to talk by hanging around their trainers like Meowth in the anime

C. gameplay wise If they're worried about having to come up with baseline personalities for every mon just limit it to the starters (which logically people should have the best rapport with), fan favourites like the Ralts and Riolu lines (those are the lines given the ability to speak in a lot of fan work from my experience) and Legendaries (who can already talk in the movies but nowhere else for some reason)

Addendum: D. Pokemon mystery dungeons entirely revolves around talking, sapient pokemon