Internationalization (i18n) refers to the process of adapting a software application to support multiple languages and locales. In a CakePHP application, you can use the i18n features to create a multilingual application that can be used by users around the world.

To use the i18n features in a CakePHP application, you will need to do the following:

1. Enable i18n support: To enable i18n support in a CakePHP application, you will need to set the ‘I18n’ key in the ‘bootstrap’ configuration to true in your application’s config/app.php file. You will also need to set the ‘defaultLocale’ configuration key to the default language for your application.

'I18n' => true,
'defaultLocale' => 'en_US',

2. Create translation files: Create a translation file for each language you want to support in your application. The translation files should be located in the src/Locale directory and should be named according to the language code. For example, a translation file for the English language should be named en.po.

3. Translate your application: Use the translation functions provided by CakePHP to translate your application. You can use the __() function to translate strings in your code, and you can use the _n() function to translate pluralized strings. For example:

echo __('Hello, World!');
echo _n('There is one apple.', 'There are {0} apples.', $count);

These examples will output the translations of the strings “Hello, World!” and “There is one apple.”/ “There are {0} apples.” in the default language specified in the ‘defaultLocale’ configuration.

By following these steps, you can use the i18n features in CakePHP to create a multilingual application that can be used by users around the world. You can refer to the CakePHP documentation for more information on the i18n features and how to use them in your application.