The Delamer's are a very united family with deep deep roots, able to track their family history very far back. Beginning a long time ago, the head of the family kept a written record of the family events.
This trait was passed to the next generation, becaming a custom, and soon the added events became, generation after generation, a full history.

This loved heritage tells of different planets, strange cultures, receipes with unknow ingredients and even -almost mytical elements- of an island surronded by turquoise water, and a city called Paris.

All this tells Tereva where he comes from, and helps to explain why his family has keep some ages long character traits and some strange slang.
This could be hidden at first, but if you hang long enough with Tereva, this will become clearly apparent.