UI design started mainly with focus for the users in west. Today, with more applications and devices being sold in BRIC nations and other emerging economies, 'internationalization' has become a common term for designers. But why are users in emerging economies so important?
If you look at some stats on the net you will notice that soon the mobile subscriptions in China will be bigger than the entire population of US. The GDP of BRIC nations is increasing and there is a huge potential for spending, due to which more products will be sold in these countries.
Hence, it is imperative for designers to think of mental models of not just 'Tim Smith' but also 'Deepak Kumar'. Designers need to take into consideration cultural perceptions into their design. What is 'good' or 'normal' in a certain culture may offensive in a different culture. Eg: In India, majority of users would be offended if you ask whether s/he has children after s/he mentions s/he has never been married. But it is OK to ask a user in Europe about children even if s/he was never married. Hence, designers need to ensure while designing forms, the marital status field always needs to be before the field on children. And put the children field to 'No' by default (with an option to say 'yes' if needed).
The above example required very subtle change to make a design global. However, at times, products need to be 'localized' for a specific country as the design is unable to accommodate a big change. Or, the interface needs to be very accommodating for various countries.
Eg: Often interface design would move from left to right on the screen. But newer users also read from top to bottom (as in Chinese or Japanese), or right to left (as in Arabic). Designers will need to shift their thinking to accommodate these differences.
In this situation, the designer needs to decide whether to 'globalize' or 'localize' the interface. The decision is based on the magnitude of application and the users who will use it. User research in countries where the product will be launched will help decide this.
In the past few companies attempted to serve these markets by simply offering their existing products with minor modifications, and many failed. Few cellphone manufacturers also had to redesign their phones to make them dust resistant and add other features (like flashlight) to make them work in rural environment. The mantra for these companies has been 'Think global, act local'.