eZ\Publish\Core\REST\Client\Values\User\User::getFieldsByLanguage PHP Method

If note set the initialLanguage of the content version is used.

public getFieldsByLanguage ( string $languageCode = null ) : eZ\Publish\API\Repository\Values\Content\Field[]
$languageCode	string
return	eZ\Publish\API\Repository\Values\Content\Field[]	With field identifier as keys

    public function getFieldsByLanguage($languageCode = null)
    {
        return $this->content->getFieldsByLanguage($languageCode);
    }

User