Final answer:
Malcolm X used self-help books and dictionaries to improve his penmanship and vocabulary.
Step-by-step explanation:
The method Malcolm X used to improve his penmanship and vocabulary was self-help books and dictionaries.
While in prison, Malcolm X discovered the Nation of Islam and embraced its teachings. He believed that Islam was the natural religion of black Americans. To educate himself and improve his language skills, Malcolm X read extensively from self-help books and dictionaries. This self-directed study helped him expand his vocabulary and improve his penmanship.