Any informations about your system? Audiocard? OS?
Do you have multiple sound devices in your system config?

I never had any problems with this game.
But you can always try an emulator like IndirectSound.
https://www.indirectsound.com/

You probably solved the problem already, but this is what a quick google brought up:

I'm not sure about Lego Star Wars but I know Lego Harry Potter has a similar problem which is fixd by changing the audio quality/ audio configuration settings so worth trying that

There are also some games that don't work well if in the system sound settings the card is set to a frequency of n * 48kHz instead of n * 44.1kHz but usually that only causes asynchron cut scenes. In on case (original version of Ghostbusters the video game) I had to set the frequencs to exactly 44.1 kHz, otherwise the speech would be pitched by log2(n-1) octaves.