I came across a copy of Dinotopia in a resale shop, so I decided to buy it and do some rereading. I loved that book as a kid, to the point that the copy I had - buried in a box at my grandmother's - has separated from its spine.
The story in the book is secondary to the beautiful art, but there are a few things about it that keep popping my suspension of disbelief. Little tiny things too - Bix can speak Hittite, but the writing system is an unmodified modern Latin script? Only one person at the Hatchery could barely speak an archaic dialect of English, but the text throughout the book is modern English in the form of dinosaur foot-script? I suppose the text shown in pictures might just coincidentally feature loanwords from English, but the Code of Dinotopia is too complex for that to carry.
I wonder what the accent of a dinosaur like Bix would be like. She's beaked, so certainly labial sounds must be difficult. Unless we're to believe dinosaurs of that sort might have parrot-like throats. That sounds plausible at least. (I later looked at a Dinotopia wiki and this does seem to be the canonical explanation; Arthur referred to her as a "hog-parrot" several times so that's not too surprising.)
The dinosaurs have modern binomial names, despite the fact that the modern system would have been invented only about a hundred years prior to the setting of the books, with literal thousands of years for the dinotopian culture to have developed their own? The Denisons calling them modern names would have made some sense, for Dinosaurs known in the 1860s at least, but Quetzalcoatlus would still be an anachronism by a good 100 years! Plus the bit about Quetzalcoatlus not understanding human or saurian languages because they're technically not dinosaurs is weird. Being unable to speak them, sure, I'd buy that, but not even learn them?
I also wonder about Dolphins - the setting as-is indicates they're sophonts, but despite that they never contacted humans outside Dinotopia? Or what about the Trilobite monuments - those died out millions of years before dinosaurs. Dinotopia must have been isolated - but "permeable" - for much, much longer than I thought the books end up indicating.
Gurney isn't a linguist or a paleontologist, and as I said the books are mostly a vehicle for cool dinosaur art. The books are great! These are little bits of sand that get into the gears for me though. I end up thinking about this stuff in parallel to the story. It's fun as a little puzzle to try to justify, I guess, if mildly distracting.