The other day, my walking buddy and I were discussing the use and misuse of slang in SF and fantasy. She was particularly exercised over an author whose entire repertoire of “future speak” seemed to consist of awkward and obvious portmanteau words like “carrocoli” for a hybrid carrot-broccoli plant. This is really more a matter of naming things than slang, but it falls into the same problem category: how does a writer make characters sound both believably futuristic (or fantastical) and comprehensible at the same time?
There are three different areas a writer has to consider when thinking about how people in a completely different place and time would talk: what to call things, what sort of slang and idioms people use, and what sort of technical jargon each of the characters could/would/should slip into their dialog.
The first is the naming of names – that is, what to call various common objects that the reader will be unfamiliar with. In most SF, the things are unfamiliar because they’re things that haven’t been invented yet, or things that come from other planets or alien societies; in medieval fantasy, they’re unfamiliar either because most people no longer have experience with a wide variety of formerly-common things and activities, from sailing a tall ship to shearing a sheep, or because the things are imaginary (like the spices the dwarves use or the herbs the elves grow).
The real things, like the parts of a harness or the names of the different sails on a schooner, the writer can find out from research. The imaginary ones need to “sound real,” and that means considering what the thing is, what it’s used for, where it came from, and possibly who invented it and when. Regardless of what something is originally named, if it’s a common everyday item that’s in constant use, the name will eventually get shortened to something easy to say: television to TV, telephone to phone, automobile to car. Names of existing items can get transferred to new ones – “notebook” is both a shorter form of “notebook computer” and a repurposing of the word that used to mean “blank pages bound in a cover to jot things down in.”
Who invented and named it is also relevant. Anything that came out of a big corporate research program will have had oodles of marketing people involved in making up the name, the way drugs and new car models do. Hybrid vegetables and fruits are often given portmanteau names like limequat, or variations on one of the names they started with, like broccolini. Things that were developed or invented in another culture sometimes keep their original name; other times, the name will be adapted, or something will be completely renamed.
The second thing to consider is slang and speech patterns. Anyone who’s read Chaucer can see how syntax and word choice have changed in the past 900 years or so; there’s no reason to think that similar changes won’t take place in the next 900. The problem is indicating those changes without turning one’s story into a language class project. Slang changes constantly and comes from many, many sources: abbreviations, portmanteau words, repurposed words, words and phrases borrowed from other languages, acronyms, etc. To give a plausible-seeming impression of future slang, a writer needs to use all of these possible sources, not just one (which was what my friend was complaining about in the book she’d read).
The other thing to consider is that unless the writer is doing very near-future SF, there will have been lots of slang and lots of idioms that have come along in the interim, and some of them will have stuck. We still talk about “reining in” someone who’s out of control, even though horses haven’t been part of daily life for nearly a century. If the only slang and idioms your far-future people use are a) those current in the far future and b) those that stuck around from 2013, it’s going to look a little odd. Similarly, if your medieval peasants are talking about not having the bandwidth for that, or even about telegraphing a punch, some readers will not be happy, but if the elves have interesting archery-slang and nature idioms, lots of people will be very happy indeed.
The third thing to think about, language wise, is whatever specialized jargon would be plausible for your specific characters to use. This comes in two varieties: terms that were once specialized to a particular field, but which have become commonplace so that everyone uses them; and terms that are still specific to a particular field that one of your characters is expert in.
The first sort of jargon is stuff that any of your characters might use, because it’s commonplace in whatever time you’ve set your story. “Laser” was, in the 1950s, a specialized acronym that hardly anyone besides physicists and SF fans had heard of; “byte” was, in the early 1980s, a term only computer geeks understood. In a story set in 2013 or later, it would be perfectly reasonable for pretty much any character to use them. On the other hand, unless one of your characters is a blacksmith, there’s probably not going to be a lot of need for anyone to list the names or uses of every hammer lying around the forge, and the whole reason Scotty can get away with all that engineering doubletalk about dilithium crystals is that nobody expects anyone to understand the jargon anyway.
Once you’ve thought about all this stuff and made up a rich linguistic stew for your characters to speak…think about dialing it back. Once in a while, somebody gets away with a book like Anthony Burgess’ A Clockwork Orange or Norman Spinrad’s The Void Captain’s Tale, but most of the time, it’s more effective to use a much lighter hand so that readers won’t get distracted by having to learn new syntax and slang and names and specialist jargon in every single sentence. A book that has to be decoded is seldom a fast read. Sometimes it’s worth the effort, and sometimes the story demands it, but be very sure it does (and that you can pull it off) if you’re going to try what is essential a whole new dialect that will be completely unfamiliar to every last one of your readers (because you made it up).
On the other hand, if you can make it work, it’s a heck of a lot of fun and a terrific tour de force. And if it works, fine.