Dyslexia

Dyslexia was a condition which made it difficult for certain people to read or write. (TV: The Hungry Earth)

In 2012, Judy was immune to Leximorphs because of her dyslexia. (COMIC: Sticks and Stones)

When Jo Jones thought that the Eleventh Doctor believed her to be stupid in 2010, the Doctor explained that he'd been keeping track of all his former companions. He noted that she had a thirteenth grandchild on the way and that the child would be dyslexic, and a good swimmer. (TV: Death of the Doctor)

When the Eleventh Doctor met Elliot Northover in 2020, he discovered that Elliot was dyslexic. The Doctor used Leonardo da Vinci and Albert Einstein as examples for Elliot to see that being dyslexic did not mean that you couldn't do great things. Elliot told the Doctor he preferred to listen to audio books instead of reading, and the Doctor encouraged him to continue trying. (TV: The Hungry Earth)

Reliable remedies were available for dyslexia by 2023. (PROSE: Artificial Intelligence)

Behind the scenes
Sheridan Smith revealed in the audio commentary for AUDIO: The Scapegoat that she's dyslexic, and sometimes had trouble with lines as a result. In particular, before they began recording she was under the impression that Spacegoat was the title of that story, rather than Scapegoat.