Internationalization (i18n) is a way of designing and developing a software product to function in multiple locales. This process involves identifying the locales that must be supported, designing features which support those locales, and writing code that functions equally well in any of the supported locales.

Localization (L10n) is a process of modifying or adapting a software product to fit the requirements of a particular locale. This process includes (but may not be limited to) translating the user interface, documentation and packaging, changing dialog box geometries, customizing features (if necessary), and testing the translated product to ensure that it still works (at least as well as the original). i18n is a pre-requisite for L10n.

Resource is 1. any part of a program which can appear to the user or be changed or configured by the user. 2. any piece of the program's data, as opposed to its code.

Core product is the language independent portion of a software product (as distinct from any particular localized version of that product - including the English language version). Sometimes, however, this term is used to refer to the English product as opposed to other localizations.

Useful links

http://www.mozilla.org/docs/refList/i18n/

http://www.w3.org/International/

http://hub.opensolaris.org/bin/view/Community+Group+int_localization/