Heleveen

One of the oldest derivations of an Indo-European language, it's barely spoken today, even among the most obsessive of Veleen, who tend to use Velaeni, which was derived from Heleveen.
  With some similarities to Latin, the language itself is fairly easy for an English speaker to pick up.
  For as many modern slang terms came out of Velaeni, a lot of them can be traced back to how the Heleveen language functions. It relies heavily on the use of metaphor, and clever wordplay was something enjoyed by a lot of the speakers. A few of those have carried forward to today. Interestingly, some of them seem to refer to the existence of the enhanced, which is strange since the language predates the first known Enhanced by at least 1500 years.
  Both Velaeni and Heleveen make heavy use of their idioms. The primary difference is that the Velaeni ones were in much more recent history so we can figure out where they came from. They also reference known places and people and situations, while Heleveen talks about more common objects.
  Examples:
 

• "I'd sooner eat a goat." Meaning is typically one of desperate longing and a desire to escape. Goats are not particularly popular food in Vielene/Valgrozna so it's hard to figure out.
• "Sweet feet are nobody's business. This probably also refers to goats. I think. It tends to mean that if someone is up to something creative, let them do their work.
• "Domala ansem." This one doesn't translate well. It's something like "Domala Pastry on the wall" and means that someone just threw a tantrum, probably a particularly childish one.