"Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo." is a grammatically valid sentence in the English language, used as an example of how homonyms and homophones can be used to create complicated linguistic constructs. It has been discussed in literature since 1972 when the sentence was used by William J. Rapaport, an associate professor at the University at Buffalo. It was posted to Linguist List by Rapaport in 1992. It was also featured in Steven Pinker's 1994 book The Language Instinct as an example of a sentence that is "seemingly nonsensical" but grammatical.
The sentence's intended meaning becomes clearer when it's understood that it uses the city of Buffalo, New York and the somewhat-uncommon verb "to buffalo" (meaning "to bully or intimidate"), and when the punctuation and grammar is expanded so that the sentence reads as follows: "Buffalo buffalo that Buffalo buffalo buffalo, buffalo Buffalo buffalo." The meaning becomes even clearer when synonyms are used: "Buffalo-origin bison that other Buffalo bison intimidate, themselves bully Buffalo bison."
GIVE ME A BREAK, ENGLISH!