Some useful insights into mobile phone usability and design in emerging markets in the Chicago Policy Review, based on earlier work by the GSMA. I'll pull out a couple of bits that made me re-read the piece:
First, though mobile internet access is expected to increase leading up to 2020, a majority of this will be via feature phones that require triple-tap text entry, making it very difficult to access mobile apps which aren't built for it.
Second, the lack of awareness of conceptual literacy by mobile app designers:
In many developing countries, cultural norms are the driving forces behind many consumers’ saving needs. For example, in rural parts of South Africa, it is common for people to spend the majority of their savings on funeral rituals. As a result, local people do not find a simple savings account appealing. The interpretation of a concept may vary dramatically in different cultural contexts; therefore, conceptual literacy becomes a critical consideration in mobile application designs.