The language most spoken is Threchian.
Their names sound like old Anglo-Saxon names. For some ideas, you can consult the following site: FNG.
Threchians are known by their dignified self-control, steadiness, perseverance and logic. They also place great value in the respect for their elders, particularly the head of the family, male or female. The head of the family has complete judicial control over its members, but also has the legal obligation to educate and help each member flourish.
Anyone can marry into another family. Such a person, male or female, will then be subject to the rule of the head of his/her new family, unless stated otherwise in the contract. People have been known to marry into another family, just to get away from a parent.
It is also possible, if a couple chooses too, to marry independently and form a new family. Usually, that would mean a loss of inheritance, but not always.
Gift
Upon a union it is traditional that the richest of the two families makes a Gift to the member of the union from the "poorer" family. There have been numerous legal battles over the prestige of being the one to give that gift.
Separation
Official separation doesn't require any legal paperwork and is in effect the moment one of the partners declares her or his will to live apart. It does, however, require one or more witness willing to testify. The Gift is then divided between the partners.
Concubine
The children of a male or female concubine, a person living with another without a lawful union, do not have any inheritance rights, but are protected by law.
Threchians have an obsession with recording everything. Even though their bureaucracy is rather light compared to the Empire of Xian, they produce an enormous number of documents. More over, each of those are the property of the nation. Tempering with any document is a capital offense.