Short & Sweet:
* Malaprop's Mishaps
* The Words That Got Away
* A Slip of the Tongue
* A Mis-Spoken Word
* Mangled Meanings
Funny & Playful:
* The Accidental Author
* The Unintentional Wit
* A Dictionary of Doodles
* The Language of Looney
* Wordplay Gone Wrong
Descriptive & Clever:
* From "Persecute" to "Prosecute": A Collection of Mr. Malapropisms
* "I'm a Little Dense": Misusing Words with Delight
* Lost in Translation: Adventures in Misunderstanding
* The Misadventures in Mixed-Up Vocabulary
Bonus:
* "The Cat Sat on the Mat" and Other Mishaps (plays on a familiar phrase)
Ultimately, the best title will depend on the overall tone and style of the collection. Good luck!