I see that "over" in Dutch can mean "over" or "past" in English. Does that mean that this sentence can mean both "Nineteen past eight" (as in giving the time) and "Nineteen over eight" (as in stating a fraction)?
No, the fraction is called "negentien achtste". I don't think there is any other way.
“Nineteen past eight” seems like a very strange way to tell the time to me, it’d have to be specified as “Nineteen minutes past eight” (there are exceptions like “five past”, “ten past” and “twenty past”, but “nineteen past” sounds weird), but maybe that’s a dialect thing (my dialect is mostly some form of British).
'Nineteen past eight' would be a very common response in the U.S. when asked about the time. Minutes are assumed given the context provided by the question.
Why is "eight nineteen" not allowed? After all, even if differently expressed, Eight nineteen, Nineteen minutes past eight, Acht uur negentien, Negentien over acht, and Elf voor half negen all mean the same thing: namely, 8.19.
Why not "nineteen after eight"? Native English speaker and I would use this phrase to tell the time as I also would use "Nineteen past." I think "Nineteen after" in this context, should be an accepted answer.