Why doesn't "lingvo" take the accusative in this sentence? There have been numerous examples elsewhere in the course where - after "ol" - we're expected to assume the presence of a verb before a noun and apply the accusative appropriately. Based on what I've seen elsewhere in the course, this makes me think that the sentence should read, "Nacio povas havi pli ol uni lingvon," but it doesn't. Why not?
A nation doesn't have that "one language". It just can have more than one language.