Designers in developed countries should be aware of the fact that the population in developed countries constitutes less than 10% of the world’s population, and that they are designing products for this 10%. Another four billion people belong to the socio-economic group known as the Bottom of the Pyramid (BOP). Prahalad and Hart define BOP as the people who live on less than $2 a day. The people in the BOP group cannot afford to buy most of the basic products that are familiar to us because the cost of the products and the infrastructure that the products rely on are not appropriate for them. Regarding this situation, following the Millennium Development Goals of the United Nations companies and research institutes in developed countries have been expanding projects to solve a variety of social issues for BOP, and have been developing a large number of applications, products and services.

These BOP projects present two problems. The first problem is the inefficient usage of resources. Many BOP projects have been established in a range of different countries and many different products, services and applications have been developed. In these case studies, similar problems or solutions have been confronted. In the case that the backgrounds where the problems arose were different, the projects tackled similar problems. However, if we identify the differences between the similar projects and propose appropriate solutions based on the differences, we can solve the problems more efficiently.

The second problem is the lack of a common language for stakeholders. With regard to problems in the BOP, there are a variety of stakeholders such as NGOs, companies, the local people and the administration. Also, these stakeholders have different specialities, such as design, engineering, business development, economic development, human development and policy. In this case, a common language to discuss a problem and attempt to find a solution is required. This common language is not the language which was provided unilaterally but a language which people can use and discuss.

Referring to the history of design, we can find a kind of common language in Pattern Language in architecture. Pattern Language was originally developed by architect Christopher Alexander. It consists of a collection of design patterns used as a common language that forms a bridge between architects and users. A design pattern is a design method with the purpose of offering a solution to a specific problem regarding design within a specific context. Alexander’s pattern language has two features: ‘format’ and ‘hierarchy’. The format consists of a style used to describe a design pattern that consists of basic components such as problem, context, and solution. This style aims to provide a proven solution to a problem of design which is easily understood by the end user as well as by the architect. Hierarchy refers to the relationship between patterns. These relationships have two characteristics: deconstruction from the abstract and large-scale to the concrete and small scale and a close connection between each pattern. When a design pattern has a structure of hierarchy, it can be called a Pattern Language.