I would encourage you to encourage your writers not to use the word "tribe" (Pambazuka News 167). For a complete explanation see Thank you for your consideration.
Extract from above URL:
Tribe does not convey the depth of history, tradition, arts, social structure, cuisine, dress, ethics and rituals that these groups developed. We don't speak of the "tribes of Europe," usually "ethnic group" or nationality is used. Similarly Native Americans had their "nations" and confedera...read more