Galaktika

noun
The shared language of the League of All Worlds.
Origin
Corruption of ‘galactic’.
Source
City of Illusions

Marain

noun
The shared constructed language of the Culture.
Origin
Possibly derived from maireannach (long-lived).
Source
Consider Phlebas

Newspeak

noun
The language of Oceania, devised to meet the ideological needs of Ingsoc.
Source
Nineteen Eighty-Four

Nadsat

noun
  1. A youth dialect.
  2. A teenager.
Origin
-надцать, the Russian equivalent of ‘-teen’.
Source
A Clockwork Orange

Cityspeak

noun
A multilingual street dialect.
Source
Blade Runner