diff --git a/src/server/internalServer.cpp b/src/server/internalServer.cpp
index 538fa2473..544f7e31f 100644
--- a/src/server/internalServer.cpp
+++ b/src/server/internalServer.cpp
@@ -754,7 +754,8 @@ std::unique_ptr<Response> InternalServer::handle_viewer_settings(const RequestCo
   const kainjow::mustache::object data{
     {"enable_toolbar", m_withTaskbar ? "true" : "false" },
     {"enable_link_blocking", m_blockExternalLinks ? "true" : "false" },
-    {"enable_library_button", m_withLibraryButton ? "true" : "false" }
+    {"enable_library_button", m_withLibraryButton ? "true" : "false" },
+    {"default_user_language", request.get_user_language() }
   };
   return ContentResponse::build(*this, RESOURCE::templates::viewer_settings_js, data, "application/javascript; charset=utf-8");
 }
diff --git a/static/templates/viewer_settings.js b/static/templates/viewer_settings.js
index 0ccf6579f..37669bb17 100644
--- a/static/templates/viewer_settings.js
+++ b/static/templates/viewer_settings.js
@@ -1,5 +1,6 @@
 const viewerSettings = {
   toolbarEnabled:       {{enable_toolbar}},
   linkBlockingEnabled:  {{enable_link_blocking}},
-  libraryButtonEnabled: {{enable_library_button}}
+  libraryButtonEnabled: {{enable_library_button}},
+  defaultUserLanguage:  "{{default_user_language}}"
 }
diff --git a/test/server.cpp b/test/server.cpp
index 520f89ce3..72670d074 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -1926,7 +1926,8 @@ TEST_F(ServerTest, viewerSettings)
 R"(const viewerSettings = {
   toolbarEnabled:       false,
   linkBlockingEnabled:  false,
-  libraryButtonEnabled: false
+  libraryButtonEnabled: false,
+  defaultUserLanguage:  "en"
 }
 )");
   }
@@ -1937,7 +1938,8 @@ R"(const viewerSettings = {
 R"(const viewerSettings = {
   toolbarEnabled:       false,
   linkBlockingEnabled:  true,
-  libraryButtonEnabled: false
+  libraryButtonEnabled: false,
+  defaultUserLanguage:  "en"
 }
 )");
   }
@@ -1948,7 +1950,8 @@ R"(const viewerSettings = {
 R"(const viewerSettings = {
   toolbarEnabled:       true,
   linkBlockingEnabled:  false,
-  libraryButtonEnabled: false
+  libraryButtonEnabled: false,
+  defaultUserLanguage:  "en"
 }
 )");
   }
@@ -1959,7 +1962,47 @@ R"(const viewerSettings = {
 R"(const viewerSettings = {
   toolbarEnabled:       true,
   linkBlockingEnabled:  false,
-  libraryButtonEnabled: true
+  libraryButtonEnabled: true,
+  defaultUserLanguage:  "en"
+}
+)");
+  }
+
+  {
+    resetServer(ZimFileServer::WITH_TASKBAR_AND_LIBRARY_BUTTON);
+    const Headers headers{ {"Accept-Language", "fr"} };
+    ASSERT_EQ(zfs1_->GET("/ROOT%23%3F/viewer_settings.js", headers)->body,
+R"(const viewerSettings = {
+  toolbarEnabled:       true,
+  linkBlockingEnabled:  false,
+  libraryButtonEnabled: true,
+  defaultUserLanguage:  "fr"
+}
+)");
+  }
+
+  {
+    resetServer(ZimFileServer::WITH_TASKBAR_AND_LIBRARY_BUTTON);
+    const Headers headers{ {"Accept-Language", "test;q=0.2, en;q=0.9"} };
+    ASSERT_EQ(zfs1_->GET("/ROOT%23%3F/viewer_settings.js", headers)->body,
+R"(const viewerSettings = {
+  toolbarEnabled:       true,
+  linkBlockingEnabled:  false,
+  libraryButtonEnabled: true,
+  defaultUserLanguage:  "en"
+}
+)");
+  }
+
+  {
+    resetServer(ZimFileServer::WITH_TASKBAR_AND_LIBRARY_BUTTON);
+    const Headers headers{ {"Accept-Language", "test;q=0.9, en;q=0.2"} };
+    ASSERT_EQ(zfs1_->GET("/ROOT%23%3F/viewer_settings.js", headers)->body,
+R"(const viewerSettings = {
+  toolbarEnabled:       true,
+  linkBlockingEnabled:  false,
+  libraryButtonEnabled: true,
+  defaultUserLanguage:  "test"
 }
 )");
   }