The big problem with translating practically anything poetic (or religious) into English is that we’re missing an intimate second person singular. For all practical purposes, anyway. You can tell people till you’re blue in the face that “thou” is an intimate, familiar, highly personal pronoun; but the distinction between “thou” and “you” in native speakers’ hearts really died out somewhere in the 1800’s.
(“You” still has a comparatively harsh sound when sung, because the y tends to front itself instead of staying liquid. This really shows up if you use it for the first word in a song line. “Thou” has a nice soft sound to the consonant, although the vowel is lacking something as a pretty singing sound. It’s too bad we can’t go back to a “thu” sound, like in Old and Middle English.)
The same thing is happening in Spanish, but the other way ’round. Its y’all form pretty much died out everywhere except Spain and Argentina; and Usted, the formal 2nd person singular (which uses third person singular grammar), seems to be dying out now also. It makes people feel old and stuffy and disliked to be addressed as Usted, even if the people addressing them don’t know them from Adam. Artificial intimacy, perhaps, but that’s what they want. Of course, that rather destroys the intimacy of reserving “tu” for close family members, loved ones, pets, children, and God. Pretty soon, they won’t have any thou/you distinction, either.
Such a fundamental Indo-European thing to lose… People carry the basic words all the way from the mists of prehistory and the forgotten steppes, through thousands of years of distinguishing between acquaintances and intimates, of changing forms of address as soon as you step across the home threshold. And now, we drop it so easily, not even noticing it go.
The funny thing is that people do sorta kinda reinvent the distinction. A lot of people assume that “thou” must be a pronoun of distant respect, because they associate it with formal things from long ago. So I suppose it’s possible that the distinction will flip. It wouldn’t be the strangest thing that a word pair’s ever done.
We reinvent it in life, too. Think of all the friending and following and social networking and posts locked to all but a few chosen eyes. It’s as if, without the words to make it normal and natural, people are constantly flaunting their intimacy with each other, toward outsiders and toward each other.
Meanwhile, I still have to decide what to do with foreign language songs and poems where every line starts, intimately, with “Tu” or “Te”.