In Attack of The Clones, there's a point when Obi Wan meets Jango Fett. During the middle of the meeting, Jango says something in what sounded like another language to his son Boba, probably because he didn't want Obi Wan to understand what he was saying. What language was he speaking in? In Legends, it seems like it could be Mandalorian, but that doesn't make sense, because Jango isn't Mandalorian in canon. Does any canon material say what language that was?
The film's junior novelisation just says that it's a "coded" language, presumably something that Jango has taught his son to allow them to communicate without worrying about being overheard
There was none, nor did Jango Fett move a centimeter out of Obi-Wan’s line of sight, and when the Jedi tried to subtly alter his angle to gain a view, Jango said, in a coded language, “Boba, close the door.”
Interestingly the Scholastic Young Reader book Boba Fett: The Fight to Survive (which also contains the scene) indicates that it's plain Huttese.
“Boba, close the door,” said Jango in Huttese, a language they both knew well.
Boba did what his father asked, never taking his eyes off the Jedi. He wanted him to feel his hate.
And the screenplay at the rear of the Art of Star Wars II, Attack of the Clones factbook agrees with this.
That being said, this doesn't make a lot of sense since it's quite likely that a well-educated Jedi would know at least a smattering of that language, hence why they seem to have changed it.
Uh Boba, rood eht so-heeck
It is different in different versions of the story. In one it's "a coded language," in another, it's Huttese, in another, Mandalorian. They probably never officially decided what exactly the language they were using was.