Treecats and Humans can't talk to each other, (vocal communication vs telepathy), and so end up coming up with different names for all of the same things. Cue a pair of Treecat mirror-twins, with one twin having darker stripes on his left side, and the other having a matched set of stripes on his right side. By coincidence, the humans and treecats call these two by the same names: Left-Stripe and Right-Stripe.
In Fire Season, young (but quickly growing up) Stephanie Harrington is severely twitterpated over a handsome boy by the name of Anders Whittaker, who is accompanying his father on an expedition to study the Sphinxian Treecats. Her treecat companion, Climbs Quickly, is troubled by his companion's agitated emotional state, and unsure of what's wrong. His sister spells it out for him, and only now, after knowing her for a book and a half, does he realize that Stephanie is not an adult, but an adolescent human going through all of the same problems that adolescent treecats have.
Doctor Whittaker's expedition finds itself cornered in a bog by some kind of very hungry alligator-analogue. Realizing that it is sensitive to sound, they fend it off for a time by singing obnoxious campfire songs as loud as they can.
When the local treecat clan arrives with Stephanie and company to help them, the 'cats use pretty much the exact same strategy, collectively issuing forth a sound described as being ear-splittingly painful even for the humans.