Audio/speech detection, verification
wav files generally have uncompressed data. That means you can get the exact waveform of the speech signal in digital form. You can tell whether the signal has some speech or not by calculating energy and using threshold to make the decision. 

Again, the above technique may not work if there is noise along with speech. 

Speech signal is quasi stationary signal and same speech will have different waveforms based on who is speaking, his pitch, his slang, his emotion and many more factors. So, it is very difficult to match two speech files. 

The two problems that you wanted to solve


% of match between two files.
Detect noise.


are special fields in signal processing by itself. First one can be achieved by doing speech recognition on both the files and get the exact text for both files and then decide some rules to get % of match. For example, even though waveform of both speech are different but content is same, only with speech recognition you can 100% match. 

coming to noise in the speech signal, there is again separate field in signal processing called as noise reduction. even though the process of noise reduction is used to reduce noise, one of the steps in noise reduction is to detect noise. You can use that step to detect noise. 

But, both these topics are pure signal processing topics and i don't think you can achieve these with some simple function call or some simple python code.