Mandarin

Mandarin was a language spoken in China. (TW: The Gathering) In the 21st century, it was the most prominent language on Earth. (TW: Children of Earth: Day One) The Doctor stated that he could speak Mandarian, among other Chinese languages. (DWU: Sympathy for the Devil) Rex Matheson ran some footage through Central Intelligence Agency software to translate it from Mandarin to English. (TW: The Gathering)