Our increasing reliance on mobile applications means much of our communication is mediated with the support of predictive text systems. How do these systems impact interpersonal communication and broader society? In what ways are predictive text systems harmful, to whom, and why? In this paper, we focus on predictive text systems on mobile devices and attempt to answer these questions. We introduce the concept of a text entry intervention' as a way to evaluate predictive text systems through an interventional lens, and consider the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) of predictive text systems. We finish with a discussion of opportunities for NLP.