While looking for an answer to this problem, I found this board so decided to cross post this question of mine from Stack Overflow.
I am searching for a method of determining the similarity between an audio segment and a human voice, which is expressed numerically.
I've searched quite a bit, but what I've found so far (detailed below) doesn't really fit what I need:
One method is to use speech recognition software to obtain words from an audio segment. However, this method is unable to come up with how "similar" audio is to human speech; it can often tell whether or not there are words in the audio, but if there are no definite words, it can't tell close the audio is to having such words.
Examples: CMU Sphinx, Dragonfly, SHoUT
The more promising method is referred to as Voice Activity Detection (VAD). However, this tends to have the same problems: the algorithms / programs using VAD tend to just return whether or not the activity threshold has been reached, and no "similarity" value before or after such threshold. Alternatively, many just look for volume, not similarity to human speech.
Examples: Speex, Listener, FreeSWITCH