We Sing Microphone

[mbc07]

You could try Ishiiruka or wiispeak branches, they have some basic Wii Speak emulation code that should make the game think a microphone is plugged. You can find Ishiiruka on its own thread here in the forums but to get wiispeak you would have to manually compile Dolphin. Fortunately, I have a pre-compiled build of wiispeak that you can download here, it's vanilla Dolphin 4.0-7636 + wiispeak code...