"extracting" sound maybe using audacity

I want to take a tv commercial and extract sound from it. I want to keep the "sound" of the words, i.e. the voice but I want to "blur" the words. I wonder if anyone knows how I might do this with something like audacity? I don't want to loose the tones of the voice, but I don't want the words to sound like words or even language, more just like music.
Thank you!