Q: What is a wizard’s favorite class in school?
Explanation: To spell a word (verb) is to say each letter in the word one by one: l – e – t – t – e – r. (Spelling in English is a challenge!)
The magic words that wizards says are called spells (noun). When a wizard casts a spell, some magic will happen.
This joke is funny because it plays with the different meanings of the word spell. Here are some spells from the Harry Potter movies: