Incomplete Lyrics Of Bach's Songs/canzoni/lieder And Airs/arie/arien?

I have many of Bach songs and airs (BWV 439 - BWV 518), and a big score with all of them, downloaded from IMSP. It's that famous edition of all Bach's work. However, when I hear the audio, they repeat many times, beyond the one written down on the score, and with new lyrics!! These lyrics are not written anywhere!!!! I've tried to google this, but I had no success (in fact, I don't even know how to look for it precisely). Can anyone help me with this?

Also, I don't speak german (imagine the german of that time...), so I can't simply catch what they're singing just by listening to it.

Can you give a specific example of where this discrepancy takes place?

Ok, here's a more detailed explanation:

I've downloaded the score from IMSP. Here's the link (of on part of the songs):

http://erato.uvt.nl/files/imglnks/usimg/d/db/IMSLP04156-Bach_-_BGA_439-518.pdf

I have recordings of many of these songs. One example is BWV 439 - Ach, daß nicht die letzte Stunde. My recording is this one:

If you follow the score, you'll notice that it repeats the song all over again (even though it's not written), and with new lyrics. And them Once more!!!!

This happens with many other songs, and I don't know why!!!!

Also, I've checked that the same happens with some choral works, like BWV 269. =/

Boom!

http://www.bach-cantatas.com/CM/Ach-dass-nicht-die-letzte-Stunde.htm

and

http://www.bach-cantatas.com/INS/BWV439-00.htm

BWV Numbers are your friend.

Thanks, Tokkemon!!! There are even more lines than the ones sung, hehe!