This line of research is junk that doesn't control for the fact that the composition of their corpus changes over time in a way that reflect changes in what gen

This line of research is junk that doesn't control for the fact that the composition of their corpus changes over time in a way that reflect changes in what genres were likely to be archived in various sources, not changes in what people are talking about. See https://www.pnas.org/doi/10.1073/pnas.2115010118 https://www.pnas.org/doi/10.1073/pnas.2115010118