Some of the latter work. He had a book called New Horizons in the Study of Language and Mind, which is fairly accesible and also covers some historical work, i

Some of the latter work. He had a book called New Horizons in the Study of Language and Mind, which is fairly accesible and also covers some historical work, including the necessary underpinning of "where did language come from". His work itself isn't as interested in the way languages evolve. That would ironically fall a bit more under the some of the paradigm he replaced. So Bloomfields book on language was in that tradition and an example of the type of scholarly work that contributes to langauge change over time. De Saussere (I believe, been over a decade since I studied this) did work on synchrony vs diachrony. There are actual journals as well at any decent university library or (sizable) city library that would allow you to dip your toe in to working scholarship and get a sense of how historical linguistics works, if thats what you're interested in.