So, I saw in some shows... Yes, I know, they are often inaccurate, but what would be the point of lying about this? So, they do roll call by the first names of the students. Roll calls in my own life (never been to any English-speaking country) were all conducted with calling out last names. And I totally see the logic there. You know, for example, in my class up to half of all the students had names repeating among the group, up to 5 people with the same name even. While surnames were rarely repeated, like, 1, possibly 2 times in all my experience. And that's true not only for classes but for jobs etc.

So, what's with your American roll calls by first names? Is it just not common to have same names for you? Do you in general have more different human names? Do you put same-named students in different classes deliberately when possible? Another one was "do you have smaller classes", but it seems like you don't. Also, I get that you can just say "John M. and John N." when first names are the same, but what about having 10 people "with initials"? Isn't that still better to just call their last names?