Latin

Latin is their main spoken language. So many people from around the world who have survived The Fall of Mankind or WW3 gathered in New Aeternum, and just like most languages were derived from it a long time ago, after thousands of years, it was created by all those languages too.
Studying any language other than Latin in New Aeternum is pretty much unheard of. Any other language other than Latin is considered a dead language, and The Higher Ups  manipulated the people by telling them, "Since there are no native speakers of those languages, there is no reason to learn them." Which is ironic since Latin is a dead language in the modern age.

Spoken by

• Aeterniums