I fooled around with this for awhile and was able to reproduce the cackling sound that goes on for the speaker every now and then.

The problem isn't the speaker, it's with the batteries and synchronization.

Nearly everytime I changed batteries I had temporary speaker problem.

Here is what I did to fix the issue:

Unplug your wii entirely. Don't just turn it off so the power light still is orange (stand by). Power it right down to the light goes red. Open your wiimotes back and take out the batteries, let it sit without batteries for a few minutes and then put one of the AA's in, then about thirty seconds after that the other. Once both are in hit the synch button on the controller.

Then use the controller itself to power the wii back on once plugged in, start hitting A right away until your past the "Hit A" black screen.

Some of those steps probably arn't needed, but that's exactly how I went about fixing things.