Inspirisles
Inspirisles is a wonderful TTRPG by Hatchlings Games that aims to teach its players the basics of sign language.
The players take on the roles of Pendragons, decedents of King Arthur and Guinevere. They much go on quests to gather Belief and battle against Disbelief which is a form of dark energy eating away at the world.
The rules are straightforward with character rolling six-sided dice to try and accomplish their goals. The most interesting twist comes in the form of Shaping which asks players to perform basic sign language to evoke elemental magic. Shaping allows characters to reroll their dice and prevent others from gaining benefits from their own shaping. It is a straight-forward but fun way for players to get the basic of sign language down and possibly spark a deeper interest in it.
This is a kid-friendly game where bloodshed has been outlawed. Aside from a single image near the beginning where a Giant is removing a heart through its mouth, there is no inappropriate content to worry about.
The books is filled with signs for different sign languages and tips for how to include hearing impaired themes in a respectful manner. It even comes with youtube videos that dive further into the sign language components.
They offer free copies to educators but any one running tabletop games for kids should give this one a look.