hc that when Host and Robbie first fused the others didn’t know about them being blind and using echolocation. They just thought Echo was a cool name and that tongue clicking was sorta like a nervous tick. Also Anti is 10/10 easily annoyed and irritable and the tongue clicking just sets him on edge. Marv one day just asks, “hey uh why do you make those noises?” And Echo just looks at him blankly.