Language

Countless different spoken, written, and gestural languages were used by different cultures throughout time and space.

The Doctor had great expertise in linguistics, once claiming he could speak five billion languages. (TV: The Parting of the Ways) However he still utilised the translation circuit of his TARDIS while travelling through space and time, though this was more for the benefit of his companions. (TV: The Masque of Mandragora, The End of the World, Cold War)