Languages have evolved from the needs of different cultures, usually being evolved versions of existing languages, with very few languages not using another as a base. Usually these languages are not spoken in-game (For the sake of readability and understanding) and may only be included for the sake of a puzzle or to demonstrate characters not understanding one another.
English is a language that has remained the same for the most part, though, two different branches of English exist, one evolved from slang terminology on the internet.
Traditional English is the same as early 21st century English.
This language is the only English language acceptably used in the professional world.
"My name is Ashley, I'm a girl, I want to take over the world! Mwahaha!"
Postmodern English is a variation on English that utilizes slang terms that evolved on the internet through the 21st and 22nd centuries. This usually is a mishmash of common slang terms, references to media, and intentional misspellings.
Some still do not consider this to be its own language, but those who speak exclusively in this "Broken English" would say otherwise.
"I'm Ashley, I'm a chick, World is mine! Lololololol!"
Japanese is a language that evolved slightly due to international pressure to become a more approachable language, and for local pressure to be quicker to write.
Traditional Japanese is the same as early 21st century Japanese. It is only used in more outdated technology and more secluded regions of Japan.
It is only learned by those that wish to study ancient Japanese culture.
Optimized Japanese is a version of Japanese that is designed to require less strokes for each character.
The syntax remains unchanged.
Names for many objects are 4 letters, and those 5 letters are often compressed into one compact character to save space.
Names for people are 6 letters, those 6 letters are compressed to save space.
Demon Runic is very uniform as a language, if two words share the same meaning, they always portray a distinctly different tone, this can lead to a sentence being able to be pronounced in multiple different ways to give a different feel.
Common Demonic is the most often spoken version of Demon Runic.
It notably does not have the same sound range of English.
This variation of the language is used in some villages on earth with a primarily Demon population.
This version of the language is also used for programming, most computers aren't designed for the Demon Runic syntax.
Spanish is a language that hasn't evolved much, it is the most spoken language in the world.
Mandarin evolved in similar ways to Japanese to require less brush strokes per character.
Korean has remained mostly unchanged.
Most Local Languages are variations of existing languages. Some are Language Isolates, lacking any relation to other languages.
A majority of languages that existed in the 21st century no longer exist, most being only minor regional ones.