I know that there are different typographical traditions (E.g. Blackletter, Roman, etc.) but how did these different traditions emerge? Who were the actors who shaped them, when did one outpace the other (why do Europeans now use a Roman script rather than say Fraktur), and more broadly what are their origins?
Similarly, how did this interact with handwriting? I know that there was something called Carolingian minuscule, but were there other miniscules, did the Carolingian one branch off into multiple traditions, etc.? For that matter, in English we have "print" and "cursive" and I think this is true in German as well. How did these two different styles develop?
And how were these transmitted? I know that there are something called incunable, which I think were handwritten books, but is that one particular style of book or is it a general term. How were people taught the scripts? Through schoolbooks, tutoring, individual guides, etc.?
As a final question, how do historians actually read this? I'm struggling with reading Fraktur, let alone the various other scripts.
I'll respond to one question, about incunables or incunabula. This refers to printed books (not manuscripts) from the early period of printing in Western Europe--when printing was in its "cradle," which is what "incunabula" means: i.e. from the 1450s, until 1500 (an arbitrary cut-off date).
Some writers on printing also use "incunabula" for early printing elsewhere--"California incunabula" would be early California prints, from the 18th century, or whenever printing was introduced there. But that's a very specialized usage.