Internationalization
Internationalization, often discussed alongside localization or localisation, is the process of making the human interface of a program available in a local language.
PHP includes some internationalization capabilities, via the locale, for dates or money format, or with the ext/intl extension.
Most of the interface translations for an application are done with specific components, such as Symfony/translation. Translation of interface messages is part of this concept.
Internationalization is also called i18n, aka i, 18 letters and n. This is shorter to write. This word may be written with a z or an s, depending on the flavor of English being used.
<?php
/* Configure le script en hollandais */
setlocale(LC_ALL, 'nl_NL');
/* Affiche : vrijdag 22 december 1978 */
echo strftime('%A %e %B %Y', mktime(0, 0, 0, 12, 22, 1978));
?>