This card is bonkers for parley decks. For only 2 resources and an action (and a slot that you were propably not going to use) you get to "add" to your hand all your parley events in your discard pile. For decks that don't have a lot of draw this can be extremely valuable. Snitch, Vamp, Grift and Beguile are the prime candidates for Eldritch Tongue. Nevertheless, any other parley event should be fit. I have found myself always happy to play this card, give it a try!

With this already out on the table, you can kill any non-Elite enemy in the game with String of Curses and 2 actions and 1 total resource (but you need to have started with 2 resources to make it work.) Play it to auto evade and add the doom, then use Eldritch Tongue to use String of Curses again from your discard pile for the 2nd effect and auto kill it. And you get the 1 resource from the second play back even! Curse them directly into the grave! I'm pretty sure this works since it is not dealing them any damage, just auto defeating them.