University required one year of Latin, or two years of French, German, or Spanish. I opted to go for the 'easy' route... and took Latin. Fast forward when our company was expanding into EMEA, and had a coding gig in France. I spoke no French, the guy I was working with spoke no English, but both of us could do parsable Latin. The code comments as we worked together were priceless when the next wave of folks came in.
The optimal teaching approach may depend on the level of the material, too. Slides & notes mailed to students may be a great option for "routine" math courses, things taken by a ton of different majors, where the paths are ground so smooth by the millions of feet traveling it that the entire class can be called in advance by even a fairly green instructor, almost down to the questions they're going to get.
As you get into higher math, though, the chalkboard becomes more important, because it's a lot more like working it out in front of the student. The class is far more likely to ask questions that are going to consume a couple of boards of scribbles to answer, and the professor may not be able to anticipate it all in advance. Trying to do this on a slide is very inconvenient and I'm still yet to see a computer interface in common use that can pull it off at all.
Many of those classes I took were actually hybrid; there was a core set of projected slides that could be mailed out (though they weren't always) that set the agenda and gave the basics and results, but there was a lot of chalkboard use as well, since as long as the room is even modestly large, there's no particular need to use just one or the other.
Graduate-level graph theory in particular used the chalkboard pretty heavily for what were essentially impromptu animations, between the numbers being added to a diagram as whatever algorithm we were learning about progressed, and the gestures being used by the professor.
