I was speaking with someone I knew earlier, and they mentioned that capitalization in Latin changes the meaning - that, for instance, "optima" with the first letter capitalized means "optimist" instead of what the Unicorn dictionary defines it as: the superlative form of "bonus, bona, bonum".
I ask you Textkitters for verification. There hasn't been any mention of it in Wheelock's so far, and it is a bit mind-boggling since I was taught that the Romans didn't have capitalization. Could it be a quirk of Ecclesiastical Latin or something uncommon?
Classical Latin did not have a lower-case/upper-case distinction. That (among other things) is a later orthographic invention. As far as I know, medieval Latin was written according to the punctuation/capitalization rules of the writer's native language. In fact, medieval Latin is many times grammatically influenced by the writer's native tongue in areas such as word order, semantic range of words, etc.
"Optima" with a capital letter would likely be the name of a person (or divine being or something), who might be an optimist, but there's no convention I've heard of for capitalizing words to change their meaning. There are many different conventions for capitalization in modern Latin. One way to do it is to follow exactly the same rules as English. Likewise you could follow, say, the same rules as in Spanish, where names of people, cities, and countries are capitalized, but names of (say) languages or adjectival forms of place names (like "Italian" as opposed to "Italy") are not. Some Latin writers don't even capitalize the first word of a sentence, though some such writers still capitalize proper names.