Yes, for a couple reasons
The description for "Telepathy" says:
You form a telepathic bond with a single person you touch, enabling you to converse with that person through your thoughts. You can only have one telepathic bond at a time.
The telepathic bond specifically enables one to "converse," meaning "engage in conversation." We can assume this is distinct from simply allowing each side of the bond to hear the other's thoughts as if they'd been spoken aloud. Two people speaking at one another, when one doesn't understand the other's language (or both don't), isn't "conversation" by any reasonable standard.
How this actually functions will depend upon the shared fiction of your game. Maybe the wizard's thoughts are translated into another language inside the pyromancer's head (and vice versa), or maybe the telepathic communication is somehow outside of language, conveying meaning without ever crystallizing into words and phrases. Go nuts!
I'll also note that one of the GM principles in Dungeon World is "Be a fan of the characters." Letting the wizard use one of their first-level spells to circumvent a language barrier is definitely being a fan of that character archetype. It's just the sort of thing we'd expect a wizard to do in a fantastical action-adventure story.