California, used to be Spanish, then it was part of Mexico, then its own Republic, and then a state in the US. Kinda fun reading actually.
On the topic, I could see just about every language in the cluster being spoken by some group in the Republic. A better example might be the native american tribes after contact with the european powers. Each tribe probably had their own language, and they might have developed a trade language if the other tribes around them had something radically different. When the europeans (Amarrians and Gallente) came they picked up those languages through necessity (due to slavery or cooperation). Later, when the Republic was around, I am sure there was some attempt at a common tongue and if history is any indicator that attempt probably failed to gain any real hold (see Esperanto IRL). And now with a return to the tribes, all the individual languages are probably coming back, though there is probably a specilized common tongue that is used in certain work groups and such (like ASD Simplified Technical English being used in the aerospace industry).
So all that to say that you could make any pictographic style a Minmatar tongue, just not a major one.
Also, I know that Ravens and I think some other Caldari ships had English style letters and numbers on them, but I haven't looked at a one in game recently.