In a few places in chap. 1, additional explication would have helped.
In chap. 14, two categories, primary sign languages and alternate sign languages, are introduced.
In chap. 2, the field study that provided the empirical basis is introduced.
The presence and emergence of writing traditions and systems (orthographies) are presented in chap. 5, with discussion of their varying degrees of use.
In chap. 5, data confirm the functions of c'est-à-dire as identified in dictionaries.
In chap. 2, he further focuses on the structure of language by looking at legal fictions and metaphor.
Many readers of this journal will find chap. 2 quite helpful.
Finally, chap. 11 seeks to answer the question of how developmental patterns observed across the languages are related across the three domains.