Murder by Death, this one might interest you because it is about the rules of grammar. Not the proscriptive rules that we learn in school but the rules that can be used to describe all languages, the cascade of choices that makes each language what it is. Why subject pronouns are mandatory in French but not in Spanish. Why Germans put the verb last and all sorts of other fascinating things that are part of all languages.
This was the 'textbook' for a course that I took some years ago. I found it fascinating but I also know that I would not have gotten through it without the professor leading us through chapter by chapter. I keep promising myself that one day I will pick it up again to re-read.