Dead languages! Ones like Ancient Greek, Old English, Old Norse, Old Occitan, Old Church Slavonic... It's no accident that these examples all have "old" or "ancient" in their name. They can still be understood and read and studied today, but the key is that nobody is really fluent, and they're nobody's native tongue.
Using a dead language to spice up a manuscript isn’t a new concept, and it’s not just in books that you see it happening; it’s also in video games, movies, TV shows, any media that wants to give itself that extra kick of mystery. It’s true that you could make up your own language, but if there’s one already there that nobody’s using, why not take advantage of it? There’s also the bonus of people being able to catch cognates and similar words. Even if readers don’t understand whatever secretive tongue you’re wielding, it has a magnetic draw because though they have no idea what’s being said, they can still kind of relate to it.
But as with all things world-building, it helps to do your research!
Language by nature constantly changes. Dialects can take over and fade away in a matter of decades. Manners of speaking can denote age, social class, geography, personality, and education. This is no different with languages that are dead.
Take Latin for example. Latin’s been around for thousands of years, and only in the past hundred has it lost its insane popularity. Because of its cool ring and sweet spelling, a lot of people like to use it in fantasy for enchantments, incantations, and riddles. But there’s so much more to it than just using a dictionary or Google Translate.
Here’s the deal. There are a bunch of types of Latin. Some main ones are Old Latin, Classical, Vulgar, Medieval, and Renaissance. Old Latin has very few extant examples, mostly surviving in inscriptions, involving different alphabets and right-to-left writing. Classical is your typical Ancient Roman fare, very correct and stately, very appropriate for official treatises and legal documents, and generally fairly snobby. Vulgar Latin was the spoken Latin existing around the same time as Classical; “vulgar” means “common”; hence, “common” Latin that people would speak on a regular basis, that didn’t revolve around rhetoric. Medieval evolved out of Vulgar and adopted a bunch of loan words from Germanic languages of the north. And Renaissance was a Humanist attempt to quash the Medievalism out of Latin and bring it back to its former “Classical glory”.
Basically, since Rome in its heyday was huge, Latin spread to all over Europe. But since Europe was equally huge, consistency in the language was hard to keep, and dialects began to form. Vulgar Latin is kind of a blanket term that covers all the spoken dialects that eventually turned into Italian, French, Spanish, Romanian, etc. When the empire fell to Germanic tribes in the north, their words started seeping into the Latin vocabulary, corrupting it. At the same time, the Christian Church was taking over and, since there was no such thing as a Latin bible, Greekisms and Hebrewisms from translated Old Testament and Greek texts also started catching on. Translations aren’t perfect, and sometimes it’s a choice between loaning a word and losing meaning. All of this started to mess with word order, and eventually gave birth to what’s known as Medieval Latin. Medieval Latin is full of random Greek words, Hebrew sentence structures, and Germanic word orders, and newer, flowery compound words created to make things sound grander. For example, if the choice were between “nice” and “congenial”, they would choose “congenial”.
And then the Renaissance came along. And thus began the general brouhaha of “The Dark Ages have ruined everything! We must rebuild knowledge!”(Silly.) This is when the Humanists started taking over. The Humanists were basically purists; people that said that the Middle Ages were a dark, dark time in history where all good knowledge was lost and the only way to make things better was to carefully study and imitate the great Classical writers and historians. Which meant effective obliteration of Medieval Latin. It also meant people trying to show off their Latin skills by treating the language like a puzzle more complicated than it was, using every possible Classical trick or eccentricity to prove their language prowess. Which made for some pretty laughable Latin.
It’s hard to explain this in English, being that English isn’t Latin, but if you were to try and write about the moon and stars on a certain night, perhaps these would be the differences in tone between Classical, Medieval, and Trying-Too-Hard:
Classical (and thereby Renaissance): The moon is bright tonight, and the stars shine with the fervor of two souls in love.
Medieval: The moon is glowing and the stars are bright as lovers' eyes.
Wannabe Classical by a puffed-up Humanist who’s trying to show off: The lunar satellite is emitting a glow, and the stars are radiating light with the excitement of two paramours together. (Or just watch this Stephen Fry/Hugh Laurie sketch.)
Except that in reality, in Latin, the first version would be half as long as the second version, and the third version would be near incomprehensible in its needless complexity. If we actually look at things in Latin, the Classical stuff would be a lot shorter because suffixes, prefixes, and word endings imply all the pronouns, persons, genders, numbers, etc. But as time went on and Latin became everybody’s second language instead of first, things like pronouns and articles and prepositions made the tricky language easier to understand. They were greatly popularized, but you don’t actually need them.
Literally, if you wanted to say in Latin something like “I am the master,” all you would have to say would be “I master.” It would look like this: Ego dominus (sum, meaning “I am”, is implied in just the ego, meaning “I”). But you could also say “Ego dominus sum.” Or “Ego sum dominus.” Or “Sum dominus,” (where the sum would imply the I instead of the ego). Or “Dominus sum”.
Things are implied. You don’t need as many words as you do in English. And see how none of them changed? They were just added or taken away? And even the order can be messed with. Just that Classical Latin goes by the order of subject/object/verb, whereas in Medieval there’s a lot of subject/verb/object, like how it is today in English, because of the influences of people’s mother tongues. For example, in English, the Classical Latin equivalent of “I am the master” would be “The master I am”. So for all we know, Yoda was just a native Latin speaker!
Now it might seem like this whole post derailed into me just talking about Latin, but I have a point. If you’re writing a fantasy novel where your character stumbles across a book written in Latin, (or any dead language for that matter), and you decide to have little bits and phrases of Latin in your actual MS, think about who actually wrote the book. Because there are so, so many questions you can ask.
What kind of education did they have? What kind of materials did they have to read? Did they grow up reading the Latin Vulgate Bible with all its Hebrewisms and Greekisms and funny word orders, or did they grow up reading the purest of the pure of Cicero and Virgil? What kind of word order did they use? Did their native language influence it? Were they a Humanist who would have insisted on a return to the Classical, or were they more progressive and liberal with their Latin, embracing loan words and different sentence structures full of implied extra words and subject/verb/object?
Think of the possibilities!
Writing isn’t just about how things sound; it’s also about how things can look on a page. Aesthetics are really important for some people. So if you’re trying to add something like Latin to your MS and you’re dissatisfied with the look and sound of it, you should know that there are so many options you can choose from and still have it be correct. Different from options in English. You can take away full words and have the meaning stay the same. And there are so many subtleties which can tip it from one point in history to the next.
My suggestion is this: if you’re ever going to use a dead language, make friends with some people at your local university. Or even use internet forums if you don’t have any colleges near by; just be sure to double check the results. (Perhaps by posting at multiple internet forums; you’d be surprised by them, I think.) And read up on the language before asking for help so you know what to ask. You don’t have to learn the language, but the better understanding you have of it, the more effectively you’ll be able to use it in your MS and justify the choices you’ve made to your copy-editor if they ever doubt you.
Also, you know you want to look like a badass when your perfectly accurate to the time period Latin is questioned for not being correct, and you reply with a delicious retort of “Well actually, my character was not a Humanist...” and totally show off your crazy world-building skills and massive attention to detail.
Just saying. It’s not nerdy if your hero still kicks ass.
P.S. for the History Buffs: If you see something that's historically inaccurate, I welcome your knowledge in the comments below.