Topic(s): Humor, songwriting
Song lyrics are a scourge among music of all kinds, because they often diminish the relevance and importance of the music surrounding them. Many casual music listeners incorrectly value the lyrical narrative over all other aspects of the song as a whole. They follow the singer's story about his broken heart or whatever, and don't even notice that there's a 5-piece backing band holding up this dissembodied human voice.
As a result, for untrained listeners to actually "hear" music, there must either be no lyrics at all, or the lyrics must be sung in a foreign language. Hence the reputation of classical music, which is revered for its musical content precisely because it lacks intelligible lyrics. Any idiot can hear the music in a classical symphony. And operatic wailings in a foreign tongue will never be mistaken by the lay listener for a narrative. Turning to more "popular" musical forms, the critical aclaim for the music of Radiohead and Sigur Ros can be attributed largely to the unintelligible character of the singing. OK Computer was once voted "Best Album Ever that I've Listened to For A Year Without Knowing Any of the Lyrics." Imagine how many listeners would have failed to connect with the album had they actually known what Thom Yorke was saying...