I wonder how much is the reverse: we now tend to say mathematical expressions as they are written, but before this was standardised, you would just explain the

I wonder how much is the reverse: we now tend to say mathematical expressions as they are written, but before this was standardised, you would just explain the steps. Probably not "one plus two" -- I think + is essentially a variant of & which is a ligature for "et", and I guess most languages put "and" between the things being combined. But I'd be surprised if (x/y)^2 was said "x over y all squared" by many people before this notation. But the notation is clearly more designed for thinking on paper than for explaining down a phone line.