By D. M. Cornish; book 1 of Monster Blood Tattoo, etc. (Note that, while imaginative, the edgy feel of the title "Monster Blood Tattoo" doesn't seem to match the mood of the actual book, at least for me.) Also contains illustrations by the author.
Imaginary hat tip to R. J. Anderson and Carbonelle for recommending this.
This story covers Rossamünd's* departure from the foundling society (orphanage) where he was raised and his journey to his new employment. As a sweet, naive, and paradoxically timid and adventurous child, he makes a fairly appealing main character, even if he is perhaps not quite a protagonist.
The characters are all distinct, even if they have shadowy pasts, and the worldbuilding in this book is clever and fantastic, and feels well put together. Instead of merely expositing different ideas, the author gives the sense that they all fit well into the physics, biology and culture of the Half-continent. Of particular interest are the secretive cults that grow or harvest foreign organs for use by humans, either as machines or living prosthetics, and the caustic vinegar waves.
However, the most important instigation in this book is presence of monsters: it is fair to say that the antagonism between monsters and everymen has had a profound effect on history. As carbonelle points out, however, what actually makes a monster is not necessarily as clear-cut as the people of the Half-continent would have it.
Along with these clever ideas comes vocabulary; the made-up words have great verisimilitude, being based on recognizable morphemes (at least to English speakers).
My chief disappointment with this book is that the story ends so soon. While Rossamünd accomplishes what he set out in the beginning to do, there are numerous hints at more to come, and many questions to answer regarding the world and his own past.
Although the strange names and words can be overwhelming at first, requiring a significant investment into the world of the story, this ends up being an enjoyable fantasy adventure story, leaving the reader wanting more but not hanging off a cliff at the end. Recommended.
* Edited to add: The "ü" in Rossamünd is pronounced the same as the vowel in wood, could, should, etc., according to the pronunciation guide.