I’m glad you mentioned them cause I just recently did some new pics! They’re pretty much cats. Obligate carnivores, purring, meowing, doing weird chips and barks. But they are also sapient and even have limited telepathy. While they mostly use body language and whatnot with one another, they “speak” to people who aren’t of their kind by projecting their voice into the minds of those around them. It’s not all powerful and they can only project voice, not read minds or anything, but they can learn any language they want to and use that to communicate.
They’re curious and very intelligent. Most people run into the types that are basically large housecats, and while they are the most common type of sphinx, the species as a whole is still a bit more on the rare side. There are other types of sphinx, too, much much larger, but no one really gets to see one of those (as far as anyone knows).