I agree with Dicho. It's common usage that counts. If I'm comfortable singing 'cam-bric' (as opposed to came-bric) and I know my audience will be happy to hear it that way, then that's the way to sing it. If I were singing it to an audience where most folk thought 'came-bric' was the normal pronunciation, I'd probably do it that way. Language has never been, and will never be, set in stone. We can use it to either bond with others or alienate them. If I sing came-bric, most of the audience will be thinking "poor woman... nice song, but a pity she doesn't even know how to pronounce 'cam-bric'!" and if I pedantically insist on explaining that MY pronunciation is the only correct one, before/after the song, then audience alienation is probably assured!