diff --git a/WeaselSetup/WeaselSetup.cpp b/WeaselSetup/WeaselSetup.cpp
index 865e4855c..5e9378bbc 100644
--- a/WeaselSetup/WeaselSetup.cpp
+++ b/WeaselSetup/WeaselSetup.cpp
@@ -151,6 +151,26 @@ static int Run(LPTSTR lpCmdLine) {
   if (uninstalling)
     return uninstall(silent);
 
+  auto setLanguage = [](const wchar_t* language) {
+    const WCHAR KEY[] = L"Software\\Rime\\Weasel";
+    HKEY hKey;
+    LSTATUS ret = RegOpenKey(HKEY_CURRENT_USER, KEY, &hKey);
+    if (ret == ERROR_SUCCESS) {
+      ret = RegSetValueEx(hKey, L"Language", 0, REG_SZ, (const BYTE*)language,
+                          (wcslen(language) + 1) * sizeof(wchar_t));
+      RegCloseKey(hKey);
+    }
+    return ret;
+  };
+
+  if (!wcscmp(L"/ls", lpCmdLine)) {
+    return setLanguage(L"chs");
+  } else if (!wcscmp(L"/lt", lpCmdLine)) {
+    return setLanguage(L"cht");
+  } else if (!wcscmp(L"/le", lpCmdLine)) {
+    return setLanguage(L"eng");
+  }
+
   bool hans = !wcscmp(L"/s", lpCmdLine);
   if (hans)
     return install(false, silent, old_ime_support);
diff --git a/WeaselTSF/LanguageBar.cpp b/WeaselTSF/LanguageBar.cpp
index 7e535e343..13198cf72 100644
--- a/WeaselTSF/LanguageBar.cpp
+++ b/WeaselTSF/LanguageBar.cpp
@@ -34,21 +34,6 @@ static void HMENU2ITfMenu(HMENU hMenu, ITfMenu* pTfMenu) {
   }
 }
 
-static LONG RegGetStringValue(HKEY key,
-                              LPCWSTR lpSubKey,
-                              LPCWSTR lpValue,
-                              std::wstring& value) {
-  TCHAR szValue[MAX_PATH];
-  DWORD dwBufLen = MAX_PATH;
-
-  LONG lRes = RegGetValue(key, lpSubKey, lpValue, RRF_RT_REG_SZ, NULL, szValue,
-                          &dwBufLen);
-  if (lRes == ERROR_SUCCESS) {
-    value = std::wstring(szValue);
-  }
-  return lRes;
-}
-
 static LPCWSTR GetWeaselRegName() {
   LPCWSTR WEASEL_REG_NAME_;
   if (is_wow64())
diff --git a/include/WeaselUtility.h b/include/WeaselUtility.h
index 942cd8ab9..100766c62 100644
--- a/include/WeaselUtility.h
+++ b/include/WeaselUtility.h
@@ -197,7 +197,32 @@ inline std::wstring get_weasel_ime_name() {
   }
 }
 
+inline LONG RegGetStringValue(HKEY key,
+                              LPCWSTR lpSubKey,
+                              LPCWSTR lpValue,
+                              std::wstring& value) {
+  TCHAR szValue[MAX_PATH];
+  DWORD dwBufLen = MAX_PATH;
+
+  LONG lRes = RegGetValue(key, lpSubKey, lpValue, RRF_RT_REG_SZ, NULL, szValue,
+                          &dwBufLen);
+  if (lRes == ERROR_SUCCESS) {
+    value = std::wstring(szValue);
+  }
+  return lRes;
+}
+
 inline LANGID get_language_id() {
+  std::wstring lang{};
+  if (RegGetStringValue(HKEY_CURRENT_USER, L"Software\\Rime\\Weasel",
+                        L"Language", lang) == ERROR_SUCCESS) {
+    if (lang == L"chs")
+      return MAKELANGID(LANG_CHINESE, SUBLANG_CHINESE_SIMPLIFIED);
+    else if (lang == L"cht")
+      return MAKELANGID(LANG_CHINESE, SUBLANG_CHINESE_TRADITIONAL);
+    else if (lang == L"eng")
+      return MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US);
+  }
   LANGID langId = GetUserDefaultUILanguage();
   if (langId == MAKELANGID(LANG_CHINESE, SUBLANG_CHINESE_SIMPLIFIED) ||
       langId == MAKELANGID(LANG_CHINESE, SUBLANG_CHINESE_SINGAPORE)) {
@@ -210,4 +235,4 @@ inline LANGID get_language_id() {
     langId = MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US);
   }
   return langId;
-}
\ No newline at end of file
+}