This document summarizes the development and diversification of Late Modern English since 1800. It discusses the emergence of American and British English as distinct national varieties, including differences in word choice, grammar, pronunciation, and spelling. Regional dialects also developed within each national variety due to geographic, ethnic, and social factors. While American English has been more innovative, British English has also incorporated many Americanisms. Dictionaries like the Oxford English Dictionary and Webster's have helped document English variations.