If you're talking about having the code "listen" to the song and extract the lyrics, that's not going to work, at all.
The lyric are also not sent separately as a side channel of the audio stream.
There is nothing to get lyrics from, unless you're playing the track from a Karaoke CD. There, you actually have lyrics as a separate track. You can use a 3rd party library to get at that data, like, Karaoke CDG DLL | Open Source Karaoke Tools