As you probably know, crickets rub together surface structures to generate sound and communicate with other members of their species. It's become something of a mundane piece of trivia at this point, but it's really pretty cool when you think about it.
The oral communication we're more familiar with also involves rubbing pieces of integument against each other to make a noise; the two big differences are that our communication involves the forced passage of air from our pulmonary system over these noisy bits, and that all the structures involved are internalized. The fact that crickets have gone an entirely different route by instead recruiting locomotive structures and that it all occurs externally can strike you as pretty alien to our methods in the right frame of mind.
Though, in the end, that degree of difference isn't all that unexpected between ourselves and insects. But what if there was a cricket-like method of communication a little closer to home? Enter the striped tenrec of Madagascar:
The video and I have both drawn the comparison to crickets, though other than being external and occurring on the posterior end of the animal, there's not a whole lot in common between the two systems. Like humans and crickets, it involves integumentary structures rubbing against each other, but rather than coopting respiratory or locomotive structures, the tenrec makes use of modified insulation structures.
For me, the tenrec manages to feel even more alien in its method, stemming from the facts that since it's a mammal I have an expectation for similarity and that I can at least relate to locomotive structures moving against each other to make a sound. But moving dermally-derived structures, and modified hairs to boot? That's pretty weird, and pretty awesome.
At the moment, the closest comparison I can think of among tetrapods is the rattlesnake's rattle, though given the varied and amazing uses tetrapods have found for dermally-derived structures (scales, feathers, hair), I wouldn't be surprised if there are more examples out there. Share any you're aware of!