Sittuun (language)
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The Sittuun language could not be spoken or understood by humans. The TARDIS's translation circuits were also incapable of translating the language, due to its complexity.
As such, being quite capable of speaking human languages as well, the Sittuun often used human names for themselves and things in their society, as a way of being understandable to their human neighbours. (PROSE: Night of the Humans)
