Well, technically, who ever said that N HAD to be silent? Yes, yes, hit me with that "traditional Pokemon protagonist silent personality" stuff. Yes it would be different. Yes, it might mess up things. However, if Game Freak found out a way to work this out then I would like that. It would add a lot of content if this happened. Sure you might be startled to find a text box with actual words instead of the regular-
".... ....... ..... ..... .... .... .... ..... ...
.... .... .... ...... ..... ..... ... .... ......"
but hey, it would be intriguing to see this-
"Yeah I'm N and haters gonna hate me and my beautiful Rubix Cube."
No wait, THIS-
"So I planned to show the world who I, N, wanted for the innocent Pokemon of this world."
This could be Post-Game like a sort of flashback for N. Or a Wi-Fi event as Magmaruby and Aquasapphire said. Or some random event in the game.
Also, if this was for the whole game then no. I just want to see this as extra content, not for the whole game.