Words and structures change their meaning over time. The text of laws, however, does not. These two facts make it difficult for judges and others, from the U.S. Supreme Court to the American people, to understand and interpret texts such as the Constitution. Current trends in legal interpretation, in particular the originalist insistence on original public meaning as the primary determinant of a law’s interpretation, make an appropriate historical linguistic understanding urgent – e.g., what did “bear arms” or “the recess of the Senate” mean in 1789? Just as important, how can we determine this? While the Supreme Court has relied heavily on eighteenth-century dictionaries in deciding recent constitutional questions, advances in theoretical and computational linguistics, as well as vast new corpora of English, make it possible for us to determine for the first time with precision what lexical shifts have occurred over the past two centuries, how these shifts have affected both the diachronic semantics of words and phrases, and their syntactic distributions. The results of such inquiries can and should have direct application to questions of statutory and constitutional interpretation. Our project aimed to help create a new methodology at the intersection of law and linguistics, yielding results and models that will change the way legal interpretation is conducted. As part of this project, we developed useable online tools and guides for other researchers and judges to conduct such inquires on their own, and to disseminated these insights and to stimulate cross-disciplinary dialogue between leading scholars of linguistic semantics and of legal interpretation.