Linguistic relativity, the idea that language affects the way that people think, and that people who speak different languages think differently, has implications for mathematics education because people use different languages to teach, learn and practice mathematics. This paper reviews research on linguistic relativity and number, looking at languages with very few number words, languages with extensive and regular number systems and the order of composition of numbers. Linguistic relativity appears to involve memory more than perception. Linguistic relativity effects involving number need to be taken into account in designing mathematics education research. [For the complete proceedings, see ED597799.]