Inclusive language is ‘language free of stereotypes, implicit bias, and negative messages’. The inclusive language movement intends to ‘acknowledge diversity, convey respect to all people, be sensitive to differences, and promote equal opportunities’. However, inclusive language is an idea or a value, not a widespread, organised effort to establish a definitive set of terms. Who decides what terms to use? What are the costs and consequences of establishing these terms? To better understand the movement, I looked at it from the perspective of diffusion theory, which seeks to explain how new products, services, and ideas are adopted (diffused) in a social system over time. The theory has identified five characteristics of successful innovations: 1) high relative advantage over alternatives, 2) high compatibility with personal and social norms, 3) low complexity in adoption and use, 4) high ‘triability’ or the chance to use the innovation before adoption, and 5) high visibility that confirms the choice of adoption. By these characteristics, many inclusive language terms face substantial barriers to widespread voluntary acceptance. These same five characteristics, however, can help inform the movement by identifying which terms are more likely to be accepted. Here, I identify where non-inclusive terms appear in the language and suggest how diffusion theory can be used to assess the likelihood of their adoption.