The speech difficulty Lewis Carroll had from childhood was a stammer.
Carroll’s real name was Charles Lutwidge Dodgson, and biographical accounts describe him as acquiring a stammer in early childhood. He referred to the condition as his “hesitation,” and it remained with him throughout his life, although it did not prevent him from becoming a successful mathematician, lecturer, writer, and entertainer.
The stammer was shared by several of his siblings, and it sometimes affected his social confidence. However, accounts also describe him as skilled at mimicry, storytelling, singing, charades, and public performance. The popular claim that he stammered only around adults and spoke perfectly with children is not supported by reliable evidence.
A common mix-up connects the speech problem with the Dodo in Alice’s Adventures in Wonderland. Carroll did call himself a dodo, possibly because “Dodgson” was difficult for him to pronounce, but that explanation is speculative. Dyslexia, aphasia, and lisp are not the standard biographical descriptions of his childhood speech difficulty.