The book is clearly printed and there is a very readable introductory section
This book is aimed at user interface designers and as such it contains guidelines on what systems should be like rather than details on how to implement them. It concentrates on systems where speech recognition or synthesis is part or all of the user interface and the user is not a computer expert. Allowance is made for future improvements in the technology.
Besides explaining guidelines, the book contains a brief survey of currently-available commercial speech products (mostly Windows software) and sound hardware. One author runs a consulting firm and has included a chapter on their methods. There are a few paragraphs on universal design (which tries to make accessibility a side-effect of the general design) but not a lot on internationalisation. There are also anumber of interviews.
The book is clearly printed and there is a very readable introductory section. There are a number of technical errors (such as confusing amplitude with volume) but these do not detract from the point.
I enjoyed reading some parts of this book, especially the introductory section, but I probably wouldn't pay its full price unless I were a professional interface designer working on a speech project.