The Loom of Language is about languages.
I have been interested in languages since my big sister started learning her first foreign language and I realized there is such a thing... I was 5. So I know a lot of the things in this book.
Not all, though :-D
He has a very interesting way of presenting things, and drawing conclusions, and associating thing. Well... to me, at least.
It might not be a very... scientifically sound book, I can understand the linguistic objections, but the purpose of it is to make it easier for English speakers to dare to speak or try to understand other languages, and that it does well, I think.