I speak to my dog in complete sentences which was a mistake because now she knows every synonym for park, walk, treats, and any time we're referring to her even if we just say 'her,' 'it,' or 'the hound.' She even learned that any time we spell a word it's related to something she likes and she goes bonkers.
We had a dog once that was super smart and would learn what different words meant very rapidly. I'd say with most dogs I've had, you can go most of their life and they'll maybe learn 2-3 different words for "dinner" and you can use other words if you're trying not to excite them too much. But this dog I swear near the end of her life we would have to say ridiculous things around her like "Did you put the K9 cereal in the receptacle?" because she had learned just about every other basic way to say "did you feed the dog?".
With dogs i think the inflection in your speech is what they pick up on more so than the actual word. Same goes for spelling something out. Next time try singing it