Many companies communicate with their users in much more casual and conversational language than the formal English taught in schools. This casual writing style may help companies seem more approachable, but they may also seem to lack professionality and trustworthiness. In this study we are interested in how language formality affects people’s reactions in security-related interfaces. Through an online quantitative study we will explore these effects as well as how people perceive the formality of some major companies. Our findings could be used by companies to decide what tone they want to address users with to accomplish their security goals.