Hello,
http://forum.pirategalaxy.com/viewtopic.php?f=261&t=24459
"Communication
English is the Primary & preferred Language on All English & International Servers (Askone, Kalgan, Solaria &Aeria) controlled by the English GM Team. Please speak English in any Public or GM-Chat as the use of translators is not always accurate. For the players of other communities who want to learn about our servers, Our way of Game Play etc, an allowance for the use of their language will be tolerated. However, If you must use a Language other than English, Please use Private, Clan or Squad or Alliance Chat"
You can read it in Pirate Galaxy - Policies & Information (CoC 3.0.1)
It's not a problem when a pilot start talking in their own language, but after a while they can go to one of the other chats.
Kind regards,
Quirina