None of the clone troopers have ever spoken Mando'a in canon, however Rex has called people “kid”, including several clones, Ahsoka, and Ezra. We also hear Cody refer to his subordinates as “kid” as well, and once he refers to another clone as “son” (Chopper in the Hidden Enemy)
Additionally, in the ‘The Deserter’, Rex explains that he is fighting so “our children and their children [won’t] be forced to live under an evil I can’t well imagine.” When Cut points out that Rex can’t have kids, as it’s against the rules, Rex responds that “it doesn’t matter if it’s my children or other people’s children.” He is not denying that he doesn’t have kids, but instead implying that he sees no different between his own offspring and others’.
Therefore, there is technically more textual evidence to support the headcanon that Rex would be referred to as “Dad” instead of “ori'vod” should a member of the 501st require a familiar nickname for him. In this essay I will examine the significance of this moniker in relation to Captain Rex, and expand upon how this may change our understanding of the GAR’s interpersonal relationships
