I was intrigued by the idea that it might be unreasonable for a book to include a glossary or dictionary to explain usages for made up or unfamiliar terms. I like that this list [1] exists because I was struggling to think of such a book. But then I thought about The Lord of the Rings, and it even includes an index of terms among its appendices, which is something I remember using to revisit parts of the story when I first read it. Another book with a glossary of terms is Dune, which I found fun and reasonable to avoid trying to explain hierarchy where doing so would break the narrative flow. But maybe that just means it's not as cleverly constructed or organized as it could have been--but the trade-off has to be how to engage a wide selection of readers...

Is the complaint about the dictionary at the end because it wasn't comprehensive? I'm unreasonably curious about the book and which phrases were included and which were not.

I think all written works occur in a context that should be taken into account when thinking critically about them. That context is temporal and linguistic and is more apparent when you consider something like Beowulf in Old English or The Canterbury Tales in Middle English. Understanding it requires either a modern reinterpretation or consideration given to the sociolinguistic context in which it was written.

[1] https://www.goodreads.com/list/show/180823.Novels_with_Gloss...