This paper examines the dynamic influence of social media on the evolution of modern English vocabulary. The rise of platforms such as Twitter (X), Instagram, TikTok, and Reddit has accelerated linguistic innovation, leading to the creation, modification, and global dissemination of new words and expressions. Through the interaction of users from diverse linguistic and cultural backgrounds, social media has become both a linguistic laboratory and a vehicle for lexical change. This study explores the mechanisms of word formation in online environments, the sociolinguistic factors driving lexical innovation, and the implications of social media language for the future of English. Keywords: social media, English vocabulary, linguistic change, neologism, digital communication, internet linguistics, sociolinguistics