diff --git a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationContentEntity.php b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationContentEntity.php
index b78dbb9e40..d8fa552267 100644
--- a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationContentEntity.php
+++ b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationContentEntity.php
@@ -4,6 +4,7 @@
 
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\PathProcessor\OutboundPathProcessorInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Render\BubbleableMetadata;
@@ -110,9 +111,19 @@ public function processOutbound($path, &$options = [], Request $request = NULL,
     }
 
     if (isset($options['language']) || $langcode = $this->getLangcode($request)) {
-      // If the language option is set, unset it, so that the url language
-      // negotiator does not rewrite the url.
-      if (isset($options['language'])) {
+      // If the url comes from an interface language switcher, leave
+      // $options['language'] alone so that the interface language can be
+      // changed, and use the entity language in the query string.
+      if (isset($options['language_switch_link_type']) && $options['language_switch_link_type'] == LanguageInterface::TYPE_INTERFACE) {
+        // Language switch URLs refer to the current entity so using
+        // $request here is fine.
+        $content_entity_id = $this->getContentEntityTypeIdForCurrentRequest($request);
+        $langcode = $request->attributes->get($content_entity_id)->language()->getId();
+      }
+      // Otherwise, unset $options['language'] in order to preserve the
+      // current prefix in the url, and only allow to change the content
+      // language.
+      elseif (isset($options['language'])) {
         $langcode = $options['language']->getId();
         unset($options['language']);
       }
diff --git a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
index 7436a3f3a0..5fc0bf20d6 100644
--- a/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
+++ b/core/modules/language/src/Plugin/LanguageNegotiation/LanguageNegotiationUrl.php
@@ -198,11 +198,20 @@ public function getLanguageSwitchLinks(Request $request, $type, Url $url) {
     $query = $request->query->all();
 
     foreach ($this->languageManager->getNativeLanguages() as $language) {
+      // We need to clone the $url object to avoid using the same one for all
+      // links. When the links are rendered, options are set on the $url
+      // object, so if we use the same one, they would be set for all links.
+      $url_copy = clone $url;
+
+      // And we need to mark the links is some way, so that other language
+      // negotiators know that these URLs should not be changed.
+      $url_copy->setOption('language_switch_link_type', $type);
+
       $links[$language->getId()] = [
         // We need to clone the $url object to avoid using the same one for all
         // links. When the links are rendered, options are set on the $url
         // object, so if we use the same one, they would be set for all links.
-        'url' => clone $url,
+        'url' => $url_copy,
         'title' => $language->getName(),
         'language' => $language,
         'attributes' => ['class' => ['language-link']],