They say you learn a lot when you teach.
Mostly what you learn is
(1) You don't know the subject as well as you thought you did, or
(2) The books are wrong, or
(3) The subject has got really weird quirks and byways.
Usually you discover these things when students ask questions. For instance: What's the English word for the sound made by camels?
So far as I can tell, there isn't one. We can certainly have a stab at describing the noise - a long gutteral croak, or a low wet mournful keening. Terry Pratchett described it as "like a herd of donkeys being chainsawed"
We can attempt to *transcribe* sounds, like "woof" or "arf" for dogs, or "boc" and "cock-a-doodle-doo" for chickens, but I'm talking about a noun naming the sound or a verb indicating it's production.
Lions roar, dogs bark, small dogs yap, very small dogs yip. Cats mew or miaw, angry cats hiss, sheep and goats bleat or baa, cows low or moo, birds chirp, parrots squawk, horses neigh, pigs snort or oink, ducks quack, donkeys bray, pigeons and doves coo, wolves howl, chickens cluck and elephants trumpet.
So there's plenty of special words for animal sounds, and a selection of words for more general sounds that we can also use for animals - bears and gorillas grunt, mice squeak, tigers and panthers growl, monkeys chatter, some birds sing, and if they don't, they call or cry. Dolphins and whales also sing.
Crickets chirrup. I once read in a book about psycholinguistics that grasshoppers make six distinct sounds, with meanings like "I'm hungry", "I want to have sex" and, rather wonderfully, one used specially for "I've just had sex". But for those of us who aren't grasshopper experts (Cicadologists? Locustophiles?), they probably just chirrup too.
Hippos, rhinos, deer, reindeer, moose (or is it mooses?) oxen and bison - these join camels in the list of animals whose utterances we don't designate with a specific word. They just "grunt".
I've absolutely no idea what sloths sound like. Maybe they're too lazy to speak.
Esperanto has a word meaning "to make the sound appropriate to the animal": Blek. The closest English has to this is probably "call".
So what do humans do? That's easy, we txt.