What kind of music are you listening to? A lot of western music is not good for learning pronunciation. There is a lot of focus on 'rhymes' and a lot of musicians think it's clever to just mispronounce words to get rhymes (and/or use nonsensical combinations of words).
These are somewhat modern habits and still qualify primarily as slang or poor usage, though some claim it is it's own accent or even dialect. Too early to tell, I suppose.