AAC Core Concepts started because of my twin sons, who are affected by physical disabilities which affect their body movements and speech. As I began looking for materials that would support my sons’ language learning within the context of school subjects, I found very little available. So I began to write materials of my own to not only help my sons learn science, social studies, and other subjects in school, but to also learn how to put together their thoughts using words that could be useful in many other circumstances as well. The focus of all of this material is on high frequency words, those little words we all use every day.