I tried to find copyright information about music lyrics, but it is too confusing, because it is related to the usage.
There are lots of websites providing lyrics, but it seems they are somehow illegal (though no complaint against them). Most of them put copyright notice that the copyright holder is the owner, and some indicate that the lyrics have been contributed by users (probably claiming that they have not been copied from the commercial CD).
However, the case of copyright for published materials like books is more serious. Consider a book about music, is it needed to obtain copyright permission for including a song lyric?
It is popular to translate the lyrics of a song to another language, and the final book contains the original lyrics and its translation.
Is copyright permission needed, or it is treated as referenced materials (no need for copyright permission as we are referring to/citing the original work). Moreover, the main part of a song is its music rather than lyrics.