Through the Language Glass
A fantastic book which hopefully every Human Centred Designer has read over their summer holiday is the multi-award winning "Through the Language Glass: why the world looks different in other languages". Guy Deutscher's highly enjoyable exposition calls into question some of our most basic assumptions regarding how language affects the way we see the world. Besides being a 2010 editor's choice of the New York Times and a 2010 book-of-the-year of Economist, Spectator and Financial Times, this enjoyable read now also counts Stephen Fry among its fans and boasts a short listing for science-book-of-the-year of The Royal Society.
http://sites.google.com/site/guydeutscher/through-the-language-glass