Get all languas of the site in Drupal 8

To get languages in English:

$site_languages = \Drupal::languageManager()->getLanguages();

To get languages in native language:

$site_languages = \Drupal::languageManager()->getNativeLanguages();

foreach ($site_languages as $languagecode => $language) {

   drupal_set_message($languagecode . " - " . $language->getName() );

}