Who are they for? These materials are designed especially for people in minority languages and oral societies, but they work well in many situations.
Who can use them? Missionaries, evangelists, pastors, short term mission teams, Sunday school teachers, parents, visitors of the sick or prisoners, friends, neighbours, ... you!
"If you talk to a man in a language he understands, that goes to his head. If you talk to him in his (own) language, that goes to his heart." -- Nelson Mandela