The fact that this sentence makes sense illustrates that English is a near-isolating language which expresses meaning through word order (syntax) rather than changing the forms of words (inflection) and also demonstrates the importance of intonation. Like several other nouns, the English word "buffalo", meaning the American bison, needn't change in the plural - it's called a "zero plural" in that it is exactly the same as the singular.
In fact, the sentence "Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" can be of any length and still make sense, so it's claimed. "Buffalo!" can be understood as an imperative, telling someone to buffalo. "Buffalo, buffalo!" is telling a buffalo to buffalo. "Buffalo Buffalo buffalo" can either mean that one should buffalo Buffalo buffalo or be seen as addressing a Buffalo buffalo, telling it to buffalo. Sentences repeating the word more than eight times are allegedly also possible, although i haven't thought of any so far.
Still images in this video are licenced under the Creative Commons, with the exception of the postcard of Buffalo, New York, which is in the public domain because the copyright has expired.
Sadly, sentences like this are rare in the wild and have generally only been developed in language labs.
The end of this video is a mess. My excuse is that i'm tired. The other things about this are that it reminds me of this:
In other news, i've done this too: