Very little is known about how new words spread in language. New words are regularly identified by lexicographers, linguists, and the news media, but until recently we have not had access to sufficiently large geo-coded and time stamped datasets that would allow for the detailed analysis of the geographical diffusion of lexical items in real time. However, with the rise of social media and smart phones, it is now possible to compile very large corpora that meet these requirements, allowing for new words to be identified and mapped across time and space and for the first time. In this presentation, I identify numerous newly emerging words based on a multi-billion word corpus of American tweets from 2013-2014 and map their geographical spread across the United States.