What countries do not a have writing system for their languages?

There are several countries where some indigenous languages do not have a formal writing system. These include some indigenous languages in parts of Africa, the Americas, and Oceania. Examples of countries where certain languages lack a writing system include some regions within Papua New Guinea, parts of the Amazon rainforest in South America, and various communities in Africa. Developing writing systems for these languages can be a complex process that involves linguistic research, community engagement, and the creation of suitable orthographies.