Good practise is to sing hymns for 18 years.... I've always wanted people to know what I'm singing about, and it does help a great deal in enjoying a song, otherwise it might just as well be scat, mouth music or a tune. A song that tells a story should be understandable, otherwise, what is the point of the story. That's why - shock horror admission here - I've NEVER LIKED DYLAN!!!Over enunciation can also lead to problems though, BBC English (This is thee Elexendra Pelece) in song can be difficult to follow. Sing as you would speak, to be understood.
LTS