The name "Akatosh" comes from the ancient Ehlnofex languages where aka means 'dragon'. In their own language, the Dov simply refer to him as bormahu 'our father'.

Akatosh's nature is really complicated to unpack. What's relevant here is that he isn't an "actual" dragon, he's a Divine that takes the shape of one, so he doesn't really need a name in his children's language. Throgmar Iron-Head has a few mispelled words on the matter, if you trust his account.

He is represented as a dragon because he is said to be the father of dragons