Hmm. It could be a few different things. The main question I want to ask you, is if you have tried playing the games that were working fine before with the wiimote speaker? Some games, the wiimote speaker isn't very clear, which is mainly the fault of the game designers.
Interference could come into it as well. Where do you have your Wii setup?
02/08/2007
Mario and Sonic at the Olympic Games
Gold Coast, Queensland, Australia