Turns out, CODA's Troy Kotsur helped create the Tusken Raider sign language in The Mandalorian

gamesradar.com:

CODA actor Troy Kotsur, who just won the Oscar for Best Supporting Actor, helped create the sign language used by the Tusken Raiders in The Mandalorian and The Book of Boba Fett.

In the series, the Tusken Raiders communicate via signing, but not in American Sign Language – it's an all new language created for the show.

A 2020 interview with The Daily Moth (H/T /Film) has resurfaced following Kotsur's Oscar win, and in it, the actor, who is deaf, explains how he developed the unique language.

"I did research on the culture and environment of Tusken Raiders," he revealed. "I researched on the desert called 'sand people.' That is what Luke Skywalker calls them 'sand people.' Anyway, my goal was to avoid ASL. I made sure it became Tusken Sign Language based on their culture and environment."

Kotsur also plays a Tusken Raider in The Mandalorian – Tusken Raider Scout #1. He's also credited in The Book of Boba Fett episode 1 for creating the language. 

"This is amazing to be here on this journey, I cannot believe I'm here, thank you so much to all the members of the academy for recognizing my work," Kotsur said in Best Supporting Actor acceptance speech. "It's really amazing that our film CODA has reached out worldwide, it even reached all the way to the White House... we met a president, Joe [Biden], and Dr. Jill, and I was planning on teaching them some dirty sign language but Marlee Matlin told me to behave myself."

The Mandalorian season 3 is expected to release this holiday season, while CODA, which also won Best Picture, is streaming on Apple TV Plus now. 

If you're all caught up, check out our guide to all of 2022's major movie release dates for everything else the year has in store.