The TARDIS has an impeccable sense of timing, of humour, and of structure. She knows who and where and why and when, and though she has no voice of her own, she is a master of languages.
She keeps them tucked away, far down a corridor or five or six (depending on which way you are going, but always a sharp right past the swimming pool), and behind a great, heavy door. Upon that door is a symbol, a sign, a grouping of words etched in Gallifreyan. A warning? It depends on who you are.
She’ll let you in as long as you are curious.
Behind that door is a secret room, a large room, a beautiful room stacked floor to ceiling with row upon row of card catalogue shelves. Inside each intricate drawer is a language. The card catalogues are tall and they are many, and are crafted of every resource imaginable, depending on the origins of the languages they contain.
This is the room that the TARDIS never translates, where every language is kept in its purest form. The evolution of every Germanic strand, the rise and the death of Latin, the intricacies of Sontaran, Sycorax, Silurian. Every language lost to time, every language yet to be spoken, every cave drawing of every creature that had a story to tell.
Everything as it is meant to be heard, as it is meant to be written, whispering always to the TARDIS: forever learning, and forever teaching.
The only language unlisted, unmentionable, unspeakable, is the language of the Silence. Silence, you see, is the end of all communication.
Which may be the reason why the warning on the door reads, “Please speak up.”