As a writer I think you sing the lyric or you leave it alone. However...how about translation. One of my favourite songwriters is Dave Mallet and I sing his songs for my own pleasure but being English I find great difficulty singing "There ain't no mansion on no hill" so I sing "There is no mansion on a hill"..but the road goes on forever! Now is that changing a lyric or is it singing it in my own language/dialect? p.s. I hate it when anyone changes a word of mine, but I'm sure my lyrics could be Americanised and not suffer at all.