A very decent lengua in salsa verde can be had at Jalisco Restaurant (I'd stay away from the birria, though, which is boiled before serving, making it very tender but robbing it of flavor).
My youngest daughter was slurping down the leftovers, when The Wife, in her infinite cruelty, said, "You know what you're eating? TONGUE!!"
Jalisco Restaurant
4224 W. 31st
"Don't you ever underestimate the power of a female." Bootsy Collins