Thought you were the_ramdomizer then for a minute!
No, voice support IS in the Wii port, any greyed out settings are like that simply because the Wii port doesn't allow the toggling of them - better to check the size of the files you've got, it might be you've simply downloaded versions that don't come with voices: I was playing The Curse of Monkey Island a couple of weeks ago, with voices... but taking the original as an example, that game was first released on floppy disks, sans voices, but later received a CD version with them added: if you're on about this game for example I'm pretty sure it's a floppy disk version that you've got....