"For evangelization purposes, a people group is the largest group within which the Gospel can spread as a church planting movement without encountering barriers of understanding or acceptance." (Source: 1982 Lausanne Committee Chicago meeting.)
In most parts of the world lack of understandability acts as the main barrier and it is appropriate to define people group primarily by language, with the possibility of sub-divisions based on dialect or cultural variations. Such a list may be referred to as an ethno-linguistic list of peoples.
In other parts of the world, most notably in portions of South Asia, acceptance is a greater barrier than understandability. In these regions, caste, religious tradition, location, and common histories and legends may be used to identify the primary boundary of each people group. Language can be a secondary boundary.
Usually there is a common self-name and a sense of common identity of individuals identified with a group. What they call themselves may vary at different levels of identity, or among various sub-groups.
The work of world evangelism is to reach even these remote people groups with the glorious good news of the Gospel. Baptist Friends is a tool that can be used to bring awareness to the geographical locations of these people groups. By knowing who they are, their languages, their customs, and their locations will equip Christians with the ability to recognize and opportunity to reach on the these unreached peoples.
"And they sung a new song, saying, Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood out of every kindred, and tongue, and people, and nation;" - Revelation 5:9
Continent of Africa
http://www.peoplegroups.org/africa.aspx
Continent of Asia
http://www.peoplegroups.org/asia.aspx
Continent of Europe
http://www.peoplegroups.org/europe.aspx
Continent of North America
http://www.peoplegroups.org/namerica.aspx
Continent of South America
http://www.peoplegroups.org/samerica.aspx
Oceania (Islands of the Sea)
http://www.peoplegroups.org/Australia.aspx
Source: For more information on "What Is a People Group" visit JoshuaProject.net and PeopleGroups.org