Its a headcanon I actually applied to some of my stories as well. You can see it in Muthu, as well as Policefluffs 2. It even made its way into my ongoing tribute to Carpdime;s Avocado, where I mentioned the Waggytail breed. Of course, that doesn’t mean you can’t do your own take on it, just felt like pointing out that I did something similar as well.
No, I didn’t write the FLuffspeak primer, Feyascia did. Ohno also did a comic about it.