Perfect Pangram — A pangram that uses each letter only once, e.g., a seven-letter pangram. GN4L — Genius, No 4 Letters: You’ve reached Genius level without any four-letter words.

NPR's Ailsa Chang talks with linguist John McWhorter about his new book, Nine Nasty Words: English in the Gutter: Then, Now, and Forever, which looks at how profanities have evolved over centuries.