Question: What is it called when you mix up the letters of a word?
Disambiguated questions and answers: question: What is it called when a word or phrase is formed by mixing up or rearranging the letters of a word?
What is the disorder characterized by mixing up or reversing the order of letters of words?
answer: Anagram
Dyslexia
question: What is the condition where you mix up the letters of words?
What is it called when you rearrange letters of a word?
answer: Dyslexia
anagram
Natural Questions answer: Dyslexia (from the Wikipedia article "Characteristics of dyslexia")