What is Internationalization?

Internationalization is the process of developing a plugin so it can easily be translated into other languages. Internationalization is often abbreviated as i18n (because there are 18 letters between the letters i and n).

Why is Internationalization Important?

WordPress is used all over the world, in countries where English is not the main language. The strings in the WordPress plugins need to be coded in a special way so that can be easily translated into other languages. As a developer, you may not be able to provide localizations (meaning, changes required to the text and other things like number formats specific to a given locale (location))for all your users; however, a translator can successfully localize the theme without needing to modify the source code itself.

Read further on “How to Internationalize your Plugin“.