I’m not sure, but based on what statistics I can find, it seems most blind people aren’t congenitally blind, so they probably have some familiarity with the symbols, maybe depending on how old they were when their visual impairment manifested. And of course you could always learn the shape of an unfamiliar symbol by feeling a physical representation of it—like on embossed paper, or those letter-shaped fridge magnets—but I dunno how common it is to do that.

If you don’t know the symbol at all, though, that could definitely make things more challenging to learn, since then the notation is (even more) arbitrary. A lot of programming languages’ symbol choices are visually mnemonic: Perl has “$” for scalars, “@” for arrays, and “%” for hashes because dollar-sign looks like S for scalar, at-sign looks like A for array, and percent-sign looks like a pair of things (a key and a value), but there’s nothing about these symbols semantically or in their pronunciation that suggests their Perl meanings.