I am Polish, my husband is German and we live in the Netherlands. While we do speak Dutch and feel at home here, we do not have a Dutch identity the way our children do- that is their horizontal identity. At the same time, I was also raised in Germany, a country different from my country of birth (Poland), and speak multiple languages, and I share this trait with my children.
Children like mine are referred to as TCKs: Third Culture Kids- children raised in a different country than that of their parents. And as exciting and mind--broadening as their experiences are, the loss and grief they feel is real and often needs counselling and therapy- it is similar to the identity/ilness model you discuss in the book. TCKs often relate to other TCKs rather than places or sometimes even their parents as many of them have been send to boarding schools. In many other ways, the parents often think that just because they consider one place (their own country of birth) home, it doesn't mean that home will have the same meaning to their children. TCKs also cross borders both literally and metaphorically and are often rejected by both of the communities on the ground of not being "German/Polish/Dutch/American/etc) enough. The children often feel they don't have a home they don't feel they belong to anywhere but with other TCKs. I write a blog about my experiences as a multilingual TCK mom to multilingual TCK children at www.europeanmama.com. I believe that Far From The Tree is a book for all parents- not only those whose children are radically different, but for all who have children. Thank you so much for this book.