source/Core/Language.php
public function getTplLanguage()
    {
        if ($this->_iTplLanguageId === null) {
            $iSessLang = \OxidEsales\Eshop\Core\Registry::getSession()->getVariable('tpllanguage');
            $this->_iTplLanguageId = $this->isAdmin() ? $this->setTplLanguage($iSessLang) : $this->getBaseLanguage();
        }

        return $this->_iTplLanguageId;
    }
public function getTplLanguage()
    {
        if ($this->_iTplLanguageId === null) {
            $iSessLang = \OxidEsales\Eshop\Core\Registry::getSession()->getVariable('tpllanguage');
            $this->_iTplLanguageId = $this->isAdmin() ? $this->setTplLanguage($iSessLang) : $this->getBaseLanguage();
        }

        return $this->_iTplLanguageId;
    }
public function getTplLanguage ( ) { if ( $ this -> _iTplLanguageId === null ) { $ iSessLang = \ OxidEsales \ Eshop \ Core \ Registry :: getSession ( ) -> getVariable ( 'tpllanguage' ) ; $ this -> _iTplLanguageId = $ this -> isAdmin ( ) ? $ this -> setTplLanguage ( $ iSessLang ) : $ this -> getBaseLanguage ( ) ; } return $ this -> _iTplLanguageId ; }
Returns active shop templates language id
If it is not an admin area, template language id is same
as base shop language id

@return string
Returns active shop templates language id If it is not an admin area template language id is same as base shop language id