A reader helpfully pointed out that this phrase, along with “a Latinized mind” below, could be misunderstood as an endorsement of strong linguistic relativity or linguistic determinism — roughly, the idea that the language a person speaks determines how she can perceive the world, and that, by extension, all speakers of language X perceive the world a certain way while all speakers of language Y perceive the world a certain other way. This is not what I am saying. In fact, during editing I removed a sentence from this paragraph that I worried would be construed this way.
With the phrase “tweaking our brains to be literally more like a Roman’s” I am referring to changes in the brain that constitute the shift from not having internalized the lexicon, syntax, phonology, etc. of another language to having internalized these elements of the language. Because Latin-speaking Roman brains had internalized these elements of Latin, developing a mental representation of Latin makes our brains more like a Roman’s in this sense.
A “Latinized mind” here simply refers to a brain (I know, not necessarily the same thing as “mind” — let’s not get into that here) that has developed a mental representation of Latin in addition to its mental representation of at least one other language, and may therefore be a candidate for the cognitive boons described in the linked literature on the brain benefits of bilingualism.