The Worldbuilder Diaries: Languages and Communication
I wouldn’t say I have anything that unique in my stories by way of languages or communication methods, but I do have a couple things worth highlighting.

Disclaimer: I’m not a linguist by any means, and while I know a tiny bit of Spanish, it’s not really enough to get by on. I’m not an expert on this topic; I just experiment and make stuff up (as I do) while I’m writing. Thankfully, fantasy allows for such experimentation, and I can (more or less) make up my own rules for communication for my equally made up species/societies.
The Murkor
The Murkor people in The Relics of War have a language wholly separate from that of the rest of their world. While some Murkor also learn the “common tongue,” not all of them do.
I spent a lot of time creating words and phrases for the Murkor, though only a handful of them are ever featured in the series and related works. Their language is described as “musical” and “lilting” by other characters, and features a lot of soft j (the zh sound), along with apostrophes acting as a means to bring two words together to form one (much like contractions in English, just a little fancier?)
Most of the Murkor words were made up on the spot, and didn’t have any real world influences behind them (at least none that I’m aware of.) For the reader’s sake, I only added Murkor words or phrases sparingly in the text, usually to highlight a specific cultural ritual/custom or as emphasis in certain dialogue passages. I thought it would be easier on the reader if I mentioned they characters were speaking in Murkor or common, rather than have lines of a fictional language they’d have to decode themselves.
Still, creating the bits of Murkor language that I did for the series was an interesting challenge for me as a writer. And it was fun, in a way.
The Corodan
The Corodan from The Caein Legacy probably have the most interesting methods of communication out of any of my fictional species. The Corodan are an insectile race, and only the females possess the necessary biology to make vocalizations. But the males aren’t incapable of communication—all Corodan can signal via pheromones (though I never called it that in the books. It’s implied, but the term isn’t part of the vocabulary, and the concept isn’t one the main character would have understood. He just accepts that the Corodan can speak amongst themselves without audible sounds.)
The Corodan also operate under a hive-mind. The Hive-queen can issue commands to all of her people, and they will follow her will. She can also delegate some tasks to her underlings, usually the larger, warrior-type females like Rizzt-tok. The delegates can then influence their direct subordinates.
The females of the species can speak using their own language (a series of clicks, chirps, and vibrations), and some even learn a somewhat broken form of the humans’ tongue to facilitate communication with them.
I had a lot of fun putting the Corodan together. I’ve always had a fascination with bugs, and I think that bled through into this story significantly.
Hand Signs
One of my ongoing works in progress series, The Mage War Chronicles, features a number of assassin characters. Due to the nature of their work and the necessity of silent communication, the assassins often use hand signals to communicate. In fact, it’s expected that all apprentices to the guild be fluent in their hand signals before they’re officially inducted as full members.
I haven’t gone into much detail about the hand signs yet; they’re just referenced on occasion.
The Botanaari
The final language I wanted to highlight in this post is that of the Botanaari people from Wraith and the Revolution. They’re the only “alien” species in the book, and most Botanaari can speak English, though they prefer to speak their own tongue in private.
There are a handful of Botanaari terms I use in the book. Most reference culture-specific items or traditions, such as the briia (their version of a wedding ceremony.) I used a lot of duplicate vowels in the Botanaari language to give it an unusual feel in the text. While the main character of Wraith is human, he does have a number of important interactions with a few Botanaari.
I didn’t make quite as many rules for this fictional language as I did for the Murkor, but I feel it still has a distinctive sound.