This book has required a great deal of informant work and many hours of consultation with experts on particular languages and language groups. It is a pleasure to record my gratitude to all those who have been generous with their time and expertise, in providing examples or references, discussing data, or commenting on parts of the book: Jean Aitchison, Keith Allan, Gunilla Anderman, R. E. Asher, Stephen Barbour, Michael Barlow, Ruth Berman, Catherine Chvany, Ulrike Claudi, Joseph Clements, Richard Coates, N. E. Collinge, Francis Cornish, Merton Dagut, Anna Morpurgo Davies, Margaret Deuchar, R. M. W. Dixon, Donka Farkas, William Foley, Ives Goddard, Nigel Gotteri, Joseph Greenberg, Dick Hayward, Bernd Heine, Eugénie Henderson, Richard Hogg, Dee Ann Holisky, Dick Hudson, Jim Hurford, Larry Hyman, Ewa Jaworska, A. A. Kibrik, Ewan Klein, A. I. Kovaĺ, Graham Mallinson, Naomi Martin, Igor Meĺĉuk, Anne Mills, Ngessimo Mutaka, Yoni Neeman, Almerindo Ojeda, John Payne, David Perlmutter, Rebecca Posner, Malathi Rao, Bob Rothstein, Linda Schwartz, Roland Sussex, Karen Taylor-Browne, and W. A. A. Wilson. F. R. Palmer, who has read and commented on each draft chapter, deserves special thanks. Naturally, those listed do not necessarily agree with my analyses. Graphic representations are a great help in giving a clear account of some parts of the topic, and I am grateful to Ian Clark, Annie Read and Kevin Shaughnessy for artwork. Some examples with numerous diacritics almost required artwork too, so the word-processing skills of Carole D'Arcy, Pauline Rayner and Philippa Galloway were appreciated.