This problem started for me years ago, back in the days when we used to gathered around in the church stairwell, singing along while someone or other pounded on the guitar--invariably, someone would pop up with a verse that no one else knew, or sing slightly different lyrics to the same verse, or drop a favorite last verse of a ballad for a completely unsatisfying one--

Looking up the right lyrics turned out to be a problem right from the start, since, as we have proved over and over again, some folk songs have so many different sets of lyrics that you can't keep track of them, let alone sing them--Even "standards" often have many more verses than people generally know, and long introductions as well. Foreign songs are a double whammy, since, in addtion to the original language lyrics, they often have been translated a few times, with different results, or they have English lyrics that are only marginally related to the original ones--

You've got to sing something--

Do you choose the more complete narrative or the shorter one?

The lyrics to a well known recording, or the ones from the "original source"?

The oldest published version, or the better known revision?

The more colorful dialect version, or the more grammatical, easier to understand one?

The earthy language, or the euphemisms?

The accurate translation, or the top 40 hit?