This is a grammatically correct sentence:
Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo.
It translates to, "Bison from upstate New York who are intimidated by other bison in their community also happen to intimidate other bison in their community."
Here's why, from Wikipedia:
The sentence is unpunctuated and uses three different readings of the word "buffalo". In order of their first use, these are
- c. The city of Buffalo, New York;
- a. The animal "buffalo", in the plural (equivalent to "buffaloes"), in order to avoid articles;
- v. The verb "buffalo," meaning to bully, confuse, deceive, or intimidate.
Marking each "buffalo" with its use as shown above gives
Thus, the sentence when parsed reads as a description of the pecking order in the social hierarchy of buffaloes living in Buffalo:
- Buffaloc buffaloa Buffaloc buffaloa buffalov buffalov Buffaloc buffaloa.
- [Those] (Buffalo buffalo) [that] (Buffalo buffalo buffalo) buffalo (Buffalo buffalo).
- [Those] buffalo(es) from Buffalo [that are intimidated by] buffalo(es) from Buffalo intimidate buffalo(es) from Buffalo.
Read the entire article here. You may also want to read more about homophonous phrases.