Here's an interesting one, short and sweet - apparently Russians are able to perceive between slightly-different hues of the colour blue because their language contains more words for it.
Researchers are still trying to figure out how it works - is it that language influences perception, or does physiology influence language? No definitive proof either way as far as I can tell, but it's an interesting effect nonetheless.
http://www.nature.com/news/2007/070430/full/news070430-2.html
