Tersuran (language)

Tersuran was the language spoken by Tersurons. Instead of speech, they communicated through carefully controlled farts. Most races in the universe abhorred this practice. (TV: The Curse of Fatal Death) Along with the Delphons, the Fendahl Predator consumed the Tersurans' best forms of communication, so they had to evolve for the most tenuous forms of communication. (PROSE: The Taking of Planet 5)

Both the Ninth Doctor and spoke in Tersuran to bribe the architect of Castle Tersurus to pull the other into a trap, anticipating that the other party would bribe him.

Later, when the Master gave the Daleks the secrets of the zectronic beam, the Doctor tried to warn the Master that the Daleks would exterminate him once they were done with him. The Doctor did this in Tersuran, as the Daleks didn't have noses. (TV: The Curse of Fatal Death)