B.tech final year project (Speech Recognition software)

Question

Respected Intellectuals i m preparing my final year project which is basically a speech recognition software which will take input from user through voice and convert it into text he doesn't have to type for it.The problem that i m facing is please tell me how to compare two .WAV files and display the percentage of similarities between them.For example the module should display 50% similarity or 70% similarity between the two WAV files and so on. Please guide me I need it desperately.