Context for those who might not know: Dai Bendu is the fanmade secret language of the Jedi. Amatakka is the fanmade secret language of the slaves of Tattooine.

What if Anakin never learned Dai Bendu? Hear me out, hear me out. Normally it would be learned in early, early childhood, like, the creches. He was never really in the creches. So when he started his years as a Padawan, it wouldn't really have come up. Here's where the tragedy comes in.

Everyone just assumed that Anakin knew Dai Bendu already, but never spoke it, and they were more wary of him because of that. They thought it meant that he was rejecting them somehow, or that he didn't really want to be a part of the Order. Anakin, who grew up with Amatakka as the secret language of his people and was familiar with the concept already, thought that they didn't want to teach them their language because he wasn't really a part of the Order, and kept his distance because of that (among other reasons). Obi-Wan never realized any of this because Anakin never brought it up (because you're not supposed to Bring Up secrets like this out loud), so he didn't realize anything was wrong. Anakin never bringing this up to anyone only compounded the issue, because they thought that if he never brought up not knowing the language, he must have already known it. They thought that Obi-Wan had taught him, or something.