diff --git a/static/skin/viewer.js b/static/skin/viewer.js
index a311552db..8beec989e 100644
--- a/static/skin/viewer.js
+++ b/static/skin/viewer.js
@@ -10,13 +10,22 @@ let viewerState = {
   uiLanguage: 'en',
 };
 
+function dropUserLang(query) {
+  const q = new URLSearchParams(query);
+  q.delete('userlang');
+  const pre = (query.startsWith('?') && q.size != 0 ? '?' : '');
+  return pre + q.toString();
+}
+
 function userUrl2IframeUrl(url) {
   if ( url == '' ) {
     return blankPageUrl;
   }
 
   if ( url.startsWith('search?') ) {
-    return `${root}/${url}`;
+    const q = new URLSearchParams(url.slice("search?".length));
+    q.set('userlang', viewerState.uiLanguage);
+    return `${root}/search?${q.toString()}`;
   }
 
   return `${root}/content/${url}`;
@@ -73,7 +82,7 @@ function quasiUriEncode(s, specialSymbols) {
 function performSearch() {
   const searchbox = document.getElementById('kiwixsearchbox');
   const q = encodeURIComponent(searchbox.value);
-  gotoUrl(`/search?books.name=${currentBook}&pattern=${q}`);
+  gotoUrl(`/search?books.name=${currentBook}&pattern=${q}&userlang=${viewerState.uiLanguage}`);
 }
 
 function makeJSLink(jsCodeString, linkText, linkAttr="") {
@@ -148,7 +157,7 @@ function iframeUrl2UserUrl(url, query) {
   }
 
   if ( url == `${root}/search` ) {
-    return `search${query}`;
+    return `search${dropUserLang(query)}`;
   }
 
   url = url.slice(root.length);
@@ -537,9 +546,8 @@ function setupViewer() {
   const lang = getUserLanguage();
   setUserLanguage(lang, finishViewerSetupOnceTranslationsAreLoaded);
   viewerState.uiLanguage = lang;
-  const q = new URLSearchParams(window.location.search);
-  q.delete('userlang');
-  const rewrittenURL = makeURL(q.toString(), location.hash);
+  const cleanedUpQuery = dropUserLang(window.location.search);
+  const rewrittenURL = makeURL(cleanedUpQuery, location.hash);
   history.replaceState(viewerState, null, rewrittenURL);
 
   kiwixToolBarWrapper.style.display = 'block';
diff --git a/test/server.cpp b/test/server.cpp
index 5a0bd072e..20d14acad 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -75,7 +75,7 @@ const ResourceCollection resources200Compressible{
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/taskbar.css" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/taskbar.css?cacheid=e014a885" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/viewer.js" },
-  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=e9c025f2" },
+  { STATIC_CONTENT,  "/ROOT%23%3F/skin/viewer.js?cacheid=5fc4badf" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Poppins.ttf" },
   { STATIC_CONTENT,  "/ROOT%23%3F/skin/fonts/Poppins.ttf?cacheid=af705837" },
   { DYNAMIC_CONTENT, "/ROOT%23%3F/skin/fonts/Roboto.ttf" },
@@ -320,7 +320,7 @@ R"EXPECTEDRESULT(    <link type="text/css" href="./skin/kiwix.css?cacheid=2158fa
     <link type="text/css" href="./skin/autoComplete/css/autoComplete.css?cacheid=ef30cd42" rel="Stylesheet" />
     <script type="module" src="./skin/i18n.js?cacheid=071abc9a" defer></script>
     <script type="text/javascript" src="./skin/languages.js?cacheid=c41aae47" defer></script>
-    <script type="text/javascript" src="./skin/viewer.js?cacheid=e9c025f2" defer></script>
+    <script type="text/javascript" src="./skin/viewer.js?cacheid=5fc4badf" defer></script>
     <script type="text/javascript" src="./skin/autoComplete/autoComplete.min.js?cacheid=1191aaaf"></script>
       const blankPageUrl = root + "/skin/blank.html?cacheid=6b1fa032";
           <label for="kiwix_button_show_toggle"><img src="./skin/caret.png?cacheid=22b942b4" alt=""></label>