So You Like to Read the Young Wizards Series

There's been an idea running around my head for a couple of weeks now that's given me some questions about how the Manual works in forms other than the book/technology forms that we mostly see it in the books. AWAB mentions how some wizards get the manual as a subconscious "knowledge" type thing, and have to memorize parts of it, but how do the wizards with oral Manuals start off?

Second, I know that the Speech registers as one's native language when spoken, but does this happen when the Speech is written? I think this may have been mentioned in Wizard's Holiday, but I can't remember.

And last thing: How exactly did wizardry work in premodern times with the smaller amount of scientific knowledge than we have today? I'm curious how much the Manual grows, if at all, with human knowledge. It may be that people in previous times just had a lot more to learn in basics from the Manual, but I have no idea, really.

Any thoughts on this stuff? Kind of theoretical, but I figured this was the best place to ask. :)