The internet has changed the norms for how we write and communicate. Many major technology companies communicate with their users in much more casual and conversational language than the formal written English taught in schools. For instance, contractions and sentence fragments are common, the word “like” often used in place of “such as”, and “info” often used instead of “information”. This casual writing style may help users view a company as more approachable, but they may also perceive the casualness as lacking professionality and trustworthiness. Trust and taking the right action are especially important in security-related interfaces, as a user’s security and privacy may be compromised if an interface fails to educate users on secure behaviors. Through an online quantitative study we will explore the effects that formality of language has in security-related prompts. These effects include: how a user understands a prompt, their perception of the prompt’s formality, and how likely they are to take the action the prompt suggests. We will also investigate how users perceive the formality of various major technology companies and whether these perceptions match how the companies actually communicate with users. As average-level formality is different for everyone, we will analyze our results across different demographics, such as education-level, age, and the country the person grew up in. Our goal is to measure the likelihood of a person to take an action based on the wording of a security prompt, the person’s sentiments towards the prompt, and whether these depend on the person’s demographics and the company with which they are interacting. Our work serves a practical purpose, that is, helping technology companies decide what tone they want to address users with to accomplish their goals. It also serves a more theoretical purpose, in furthering understanding in the intersection of human-computer interaction and security.