How to detect the current language of a Joomla! website?

See getLanguage in JFactory:

$lang = JFactory::getLanguage();echo 'Current language is: ' . $lang->getName();

Once you have the language, you can also retrieve the locale/language code (e.g. en-US). Joomla! languages can have multiple locales, so you'll get an array.

$lang = JFactory::getLanguage();foreach($lang->getLocale()  as  $locale) {    echo 'This language supports the locale: ' . $locale;}

If for some reason, you are only interested in the first locale, you can simply grab the first element. You will probably need an array, like this:

$lang = JFactory::getLanguage();$locales = $lang->getLocale();echo 'This language\'s first locale is: ' . $locales[0];

If you just want to get the selected language tag (e.g. pt-PT) you can use getTag()

$lang = JFactory::getLanguage();echo 'Current language is: ' . $lang->getTag();

In Joomla 3.4+, the answer by @MvanGeest still works. Here's a list of useful functions that exist on the language object:

• Get a handle on the current language through an object of type JLanguage

  $currentLanguage = JFactory::getLanguage();

• Get the current language name:

  $currentLanguageName = $currentLanguage->get('name');//OR$currentLanguageName = $currentLanguage->getName();

• Check if RTL (which is the case of the Arabic language and some other languages)

  $isRTL = $currentLanguage->get('rtl');//OR$isRTL = $currentLanguage->isRtl();

• Get the current language tag:

  $currentTag = $currentLanguage->get('tag');//OR$currentTag = $currentLanguage->getTag();

• Get a list of all the known languages:

  $arrLanguages = $currentLanguage->getKnownLanguages();