c# - How do I compare 2 audio files, returning a percentage of difference

Is there a way to compare 2 audio files, whereby a percentage of difference will be returned? I am using C# VS08, .net framework 3.5.

Edited: difference in the sound (like for eg. Audio 1: "HELP", Audio 2:"HELP ME PLEASE", it will return the difference in percentage between this 2 audio.)

I am currently saving recorded files in wav format, and its bit rate and quality will also be the same as what will be recorded and compared against. I wish to ask if there is a way to compare the sound (not just the binaries) in 2 audio files of the same properties and same format (WAV), and show the percentage difference between the 2 sounds in the 2 audio files.

Help will be greatly appreciated.