The term localization describes the translation and adaptation for a local market of a program originally developed in a different market and in a different language, usually English. Localization activities include translating the user interface, resizing dialog boxes, customizing features (if necessary), and testing results to ensure that the program still works, as well as translating documentation, Help, marketing material, packaging and related Web site articles. The effectiveness and efficiency of the localization process often depend on other activities, in particular globalization and localizability.

The term globalization describes the process of developing a program core whose features and code design are not solely based on a single language or locale and as such can satisfy user expectations in different markets. The term locale  defines the collection of features of the user’s environment that is dependent on language, country/region, and cultural conventions; a locale determines conventions such as sort order, keyboard layout, as well as date, time, number, and currency formats. A typical example: the date 06/09/08 would be interpreted by an Italian as 6 September 2008, by an American as 9 June 2008 and by a Hungarian as 8 September 2006. Globalization ensures that any user in any country can correctly apply the conventions expected in his/her market, regardless of the language of the software product.

The term localizability refers to the design of the software and resources such that a program can be localized into different language editions without any changes to the source code. Planning for localizability in the early stages of a product life cycle contributes to a smoother, more efficient localization process where fewer resources are required.  

Localization, globalization and localizability are often summarized with the term internationalization, further abbreviated into I18N for the number of characters between first and last letters in the name. Microsoft, however, often prefers the term world ready  to describe a program that has been properly globalized and developed for ease of localization.

The above terms, their definitions and additional terminology related to the localization and globalization processes can be found in the Global Development and Computing Portal Glossary.