The language teens use in digital spaces--from social network posts to instant message chats to text messages--often does not adhere to Standard Written English (SWE). Their digital writing involves a combination of written and conversational languages and often has a digital thumbprint that distinguishes the writer. As a means to understand this "digitalk," we conducted a mixed method study that not only examines the conventions of digitalk, but also explores the impetus behind teens' languages choices. Over the course of 2 years and three rounds of data collection, we investigated the digital language use of 81 adolescents (Grades 7-12) from urban and suburban, public and private schools in a large metropolitan area. Data provide insight into the conventions of digitalk and the reasons these features of language have been conventionalized within adolescent digital communities. Ultimately, we see teens engaging in purposeful writing that may differ from SWE, but, nonetheless, shows an awareness of audience, efficiency in communication, expression of personal voice, and inclusion in a community of practice.