In the episode "The Christmas Invasion" the leader of the Sycorax makes it clear that he is aware that he is speaking a language that is not spoken on Earth. Despite this he expects the humans to understand what he is saying and understands them when they speak in English.
This made me curious about which of the following is true:
- Universal translators are so common that a species that is only capable of basic space travel could be expected to have one.
- Universal translators are something unique to the Time Lords/TARDIS.
- Something between these two extremes. (e.g. Most species have limited language translation capabilities, but only the Time Lords have universal translators.)
In short, how common are universal translators (i.e. devices capable of translating between any two languages instantly) in the Doctor Who universe?