I talk to my bunnies all the time. We’ve had “pee pee goes in the potty” talks, “no biting” talks, etc. Mine seem to understand “no” (although they do sometimes go right back to whatever it was as soon as I turn my back) and Kieko understands “get down” (she has almost fallen out of her condo being nosey when I’m dishing up dinner so now when I say “get down” she gets down!). I’d say talking to them (it’s more tone than anything) and re-directing them like a teacher would do is great!
Our dog had a huge vocabulary and knew what “get out of the kitchen”, benadryl, DirtyDogs (pet wash), squirrel, “go pee” “go poop”, etc. all meant. She would also play hide and seek with dog treats and would respond correctly to “cold”, “warm”, and “hot” when giving hints to where the treat was hidden. I believe that if a dog can do that, a bunny can be taught what certain words mean (they’re pretty smart, just alot more stubborn than most dogs!).
Edit: I’m sure some would say I imagined it or that it was coincidence, but I swear I had a “conversation” with Marlee one day about her being angry about something — it ended with me telling her to “get over it” and her thumping at me and giving me the butt. Either that bunny knew what I was saying or it was a mighty big coincidence that *every one* of her thumps was perfectly timed!