Songwriters and composers tend to belong to two separate leagues of musicians, that said, they both strive for an effect. If that effect is masterfully achieved then that is good music. As far as lyrics are concerned, they're only meaningful if there's something in them pertaining to the musician or listener, making them mostly irrelevant to objective criticism.
An example of an incredibly successful song whose lyrics are only inwardly meaningful to a zeitgeist of art is "Space Oddity" by David Bowie. The song's lyrics are inspired from Stanley Kubrick's 2001: Space Odyssey and imitated that film in mocking technological advances especially in space. It was such a hit that the BBC used the song as a musical accompaniment to the moon landing. Irony, eh? If the lyrics weren't so obscure to them they might have chosen a different song, but since they were taken by the pop that David Bowie is extremely good at creating, they lampooned themselves.
The difficulty in deciphering the meaning of a foreign language in lyrical form is compounded by the fact even a native speaker might not understand what a musician is trying to convey! That might explain why a hot chick with a nice body and smiling (or weeping) face will win over the hearts and not so much the (un)trained ears of the masses. Yes, I'm referencing most pop stars. Whenever someone enjoys music for it's musical integrity alone, they alter their cultural borders to become more inclusive of some people while alienating others. I've found that the saddest thing about music is the audience's inability to forget their particular biases and just let their own imaginations work. It's as if the only reason some people listen to music is because they want the music to put them into a particular mood or to sedate them. Anyways, that's my stance on why I rarely even listen to a vocalist anymore...
