It is a tradition of the British royal family to write the dinner menu in French.

The specific reasons are:

1. The British royal family originated in France and was inherited from the French royal family of Normandy.

2. George V of England liked French things very much, and he stipulated that the royal menu should be written in French.

3. France’s position in the catering industry is unshakable, and using French can bring out the specifications of the dinner party.