Accent

An Accent is how a voice sounds when speaking a second language. Although with training, one can learn how to adopt a different accent if they wish or need to.

History
The Ninth Doctor was often criticized for his accent. He would often retort "Lots of plants have a North." (TV: Rose - The Parting of the Ways) The Twelfth Doctor initially thought everyone else had changed accents (when in reality, he did), due to his post-regeneration delirium. But soon took his Scottish accent as an entitlement to complain about things. (TV: Deep Breath) He could imitate an American accent. (TV: The Zygon Inversion)

The jewel thief The Unicorn was able to imitate a posh accent while pretending to be Robina Redmond. However, she truly spoke in an East End accent. (TV: The Unicorn and the Wasp)

Jack Harkness, likely due to the centuries he lived, was able to change his accent as he wished. He demonstrated being able to imitate a Texan accent, (TV: Greeks Bearing Gifts) and an English accent. (TV: End of the Road)

Missy chose to speak in a Scottish accent, after coming to like the Twelfth Doctor's. (TV: Deep Breath) She could also imitate a Texan accent when taunting a Dalek. (TV: The Witch's Familiar)

The TARDIS translation circuit often had people confused about where the time travelers were from. At one point, both the Tenth Doctor and Donna Noble spoke Latin when their speech was already being translated into Latin; it came out sounding Celtic. (TV: The Fires of Pompeii) When Amy Pond meet Vincent Van Gogh, her speech was translated into French; however, due to her Scottish accent, Vincent thought she was from Holland. (TV: Vincent and the Doctor)