From other bread crumbs in 10.13.4 public beta 1, I have to assume the lack of dictionaries is an oversight that will be corrected in future betas. There are too many places where the dictionaries are used in too many Apple and other applications and the holes where the dictionaries should plug in are still there. Interestingly enough the spell checker still seems to be working. Is that separate from the Dictionaryâ“
Of course there is always that one fateful word "assume". 🤷â€â™‚ï¸
By-the-way, if you wonder where the Dictionary comes from I found this in Dictionary > Preferences…
That would appear to rule out any consideration of Royalties — at least for the basic dictionary content.