Summary: As much as he likes humans, there are some things the Doctor will never understand about them.
Humans are peculiar; they live on one small, nondescript planet, and despite what some of them seem to think they’re all the same species, yet they have hundreds of languages. Which he supposes might explain why they have so much trouble getting along.
Just to make things even more complicated, not content with having different languages, they confuse each other further by speaking the same language in dozens of different accents.
Having the TARDIS translating for him helps the Doctor make sense of what they’re saying, but he sometimes wonders if humans are simply determined not to understand each other.