Gotteslob 2013 has a wonderful metrical paraphrase of Psalm 137, derived from a Latvian source, to a Latvian tune. I've put it into English, if it is of use to anybody.

1. Filled with sorrow, by the weary
streams of Babylon we lay :
borne so far from cherished Zion,
cheerless lyres we put away;

2. Our eyes fixed upon our homeland,
hearts transfixed by bitter grief,
on the aspens of our exile
hang our harps no more to speak.

3. For our captors still torment us,
mocking, sneering, they demand :
"Sing for us the songs of Zion,
sing the songs of your old land!"

4. Oh, my heart! How can I sing them,
Here in exile, Zion lost?
Zion, if I e'er forget thee,
let my tongue, my hand be lost!

5. Jesus' Cross will be my refuge
from the yoke of tyranny,
and my Risen Lord will free me
from the bonds of slavery.