This should be considered cheating as they are in essence not communicating their alliances to all the players if everyone does not understand their language. Check out game #7670

as you can see from the msg's below, he offered me a truce for 2-to-3 turns but with in the next turn he went back on his word and took me out where i decided not to fortify based on our treatie

2006-03-10 20:42:56 - Chiater: hey machine, how about a brazil, north africa truce?
2006-03-12 06:50 ...