The linguistic relativity hypothesis proposes that speakers of different languages perceive and conceptualize the world differently, but do their brains reflect these differences? In English, most nouns do not provide linguistic clues to their categories, whereas most Mandarin Chinese nouns provide explicit category information, either morphologically (e.g., the morpheme vehicle "che1" in the noun for train "huo3 che1" or orthographically (e.g., the radical bug "chong2" in the character for butterfly "hu2die2"). In a series of behavioral and neuroimaging experiments I tested the behavioral responses, neural correlates, and developmental trajectory of the influence of language on categorization processes in native English and Mandarin Chinese speakers. These data suggest that both cross- and within-language differences in the explicitness of category information have strong effects on the nature of categorization processes performed by the brain. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]