diff --git a/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php b/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
index 7f3027a27671..61c4afb83e60 100644
--- a/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
+++ b/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
@@ -4501,6 +4501,10 @@ public function getData($string, $fieldArray = null)
                     case 'sitelanguage':
                         $siteLanguage = $this->getTypoScriptFrontendController()->getLanguage();
                         $config = $siteLanguage->toArray();
+                        // Harmonizing the namings from the site configuration value with the TypoScript setting
+                        if ($key === 'flag') {
+                            $key = 'flagIdentifier';
+                        }
                         if (isset($config[$key])) {
                             $retVal = $config[$key] ?? '';
                         }
diff --git a/typo3/sysext/frontend/Classes/DataProcessing/LanguageMenuProcessor.php b/typo3/sysext/frontend/Classes/DataProcessing/LanguageMenuProcessor.php
index 2249d75172e7..2c22a3ed8400 100644
--- a/typo3/sysext/frontend/Classes/DataProcessing/LanguageMenuProcessor.php
+++ b/typo3/sysext/frontend/Classes/DataProcessing/LanguageMenuProcessor.php
@@ -481,6 +481,8 @@ public function getFieldAsJson(string $content, array $conf): string
         $language = $site->getLanguageById((int)$conf['language']);
         if ($language->enabled()) {
             $language = $language->toArray();
+            // Harmonizing the namings from the site configuration value with the TypoScript setting
+            $language['flag'] = $language['flagIdentifier'];
         } else {
             return $this->jsonEncode(null);
         }