Internationalization

Internationalization, abbreviated i18n, is the design and development process that enables the later localization of software, content, and products for different languages, regions, and cultures. It involves separating code from translatable content, using locale-aware libraries, and avoiding hard-coded strings.

Key concepts include externalizing text into resource bundles or message catalogs, using locale data for formatting numbers, dates, currencies, and addresses, and handling text direction, character sets, and pluralization rules. Internationalization also covers input methods and accessibility considerations that may vary by locale.

Globalization describes the broader business and engineering effort to serve multiple locales, within which i18n is the design approach and localization (l10n) is the actual adaptation of content for a locale. Standards and data, such as Unicode for encoding, the Common Locale Data Repository (CLDR) for locale data, IANA language tags (BCP 47), and ICU libraries, support consistent, scalable i18n implementations.

Practices include starting internationalization early in product development, using translation management systems, and testing across locales. Challenges include cultural sensitivity, legal and regulatory compliance, variable text length, and performance considerations.

Applications span software, websites, mobile apps, games, and documentation; effective internationalization contributes to usability and broad market reach, whereas poor i18n can hinder user experience and increase localization costs.