Loaf Warden
(no party affiliation)
Actually, we're a little better off than that. There has been extensive work done on translating Olmec 'glyphs' and phrases. Trouble is, there is frequently no context for what they are talking about, so paragraph-sized meanings are hard to glean, and as far as I know, they haven't uncovered anything resembling a city or place-name. Result: you could end up with a 'city list' in which the cities are named "Jaguar", "turtle", "serpent", "wading through water", and other words/phrases that have nothing to do with the original cities at all - the only 'advantage' they have is that they are actual Olmec words, but that's it, and it's not much...
And even then, we're stuck calling them the "Olmec", a name given by the Aztecs to a people who, in their own time, were living in the same region that the ancient culture had lived in. Presumably the ancient Olmec had their own name for themselves, but it would not have been "Olmec", and we have no idea what it would have been. There's no way to represent the Olmec in-game--or anywhere else--without fudging the names.