Between all the dialog in A Phantom Menace and A New Hope, the various animated series (where I understand the Hutts figured prominently in some story lines) and now The Mandalorian, there has been quite a lot of Huttese on screen, much of it subtitled.
(Related: Why does Greedo say "Maclunkey" in the Mos Eisley Cantina?)
We also know that a number of SF/SFF languages have been quite extensively developed, including Klingon, Dothraki, the various languages in LOTR, etc, either by authors/producers or the fandom. And Star Wars fans can be quite a serious bunch.
What is the level of development Huttese? It is consistent within Star Wars canon? Does it have a defined grammar and vocabulary?