M. Paul Lewis served as general editor of Ethnologue: Languages of the World from 2004 to 2016, and is a Senior Consultant in Sociolinguistics with SIL International. His primary research and publication interests are in language maintenance, shift and death, language policy and planning, and language documentation. He has authored, co-authored, or edited more than 50 publications. Along with Gary F. Simons, he is a developer of the Expanded Graded Intergenerational Disruption Scale (EGIDS) and the Sustainable Use Model (SUM). Beyond his duties as general editor of the Ethnologue (www.ethnologue.com), he has primarily done research, consulting and training in sociolinguistics with SIL International in Africa, Australia, Asia, Central America, Europe and North America.

Gary F. Simons is the Chief Research Officer for SIL International (Dallas, TX) and Executive Editor of the Ethnologue (http://www.ethnologue.com/). He is also Adjunct Professor of Applied Linguistics at the Graduate Institute of Applied Linguistics (Dallas, TX). Early in his career he was involved in language development activities in Papua New Guinea and Solomon Islands.  More recently he has contributed to the development of cyberinfrastructure for linguistics as co-founder of the Open Language Archives Community (http://www.language-archives.org/) and co-developer of the ISO 639-3 standard of three-letter identifiers for all known languages of the world (http://www.sil.org/iso639-3/). He holds a PhD in general linguistics (with minor emphases in computer science and classics) from Cornell University. He is an author or editor of over 100 publications (http://www.sil.org/~simonsg/).