It has been so long since I played this game that I couldn't remember whether there were voiceovers or not, so checked
here to confirm.
Apart from looking for a possible update to your sound drivers, I would suggest writing to Big Fish Customer Support about this problem.
On the other hand, Judith, give me a few minutes and I will redownload my Big Fish CSI: New York. It's possible that the download version didn't have voice overs.