diff --git a/autobuild.xml b/autobuild.xml
index 3504bb0252..b3280f9e52 100644
--- a/autobuild.xml
+++ b/autobuild.xml
@@ -167,6 +167,34 @@
           </map>
         </map>
       </map>
+      <key>slvoice_os</key>
+      <map>
+        <key>copyright</key>
+        <string>2010 Vivox, including audio coding using Polycom¨ Siren14TM (ITU-T Rec. G.722.1 Annex C)</string>
+        <key>description</key>
+        <string>Vivox SDK components compatible with OpenSim</string>
+        <key>license</key>
+        <string>Mixed</string>
+        <key>license_file</key>
+        <string>LICENSES/slvoice_os.txt</string>
+        <key>name</key>
+        <string>slvoice_os</string>
+        <key>platforms</key>
+        <map>
+          <key>windows</key>
+          <map>
+            <key>archive</key>
+            <map>
+              <key>hash</key>
+              <string>9676f61f3e32dfce50550004be559519</string>
+              <key>url</key>
+              <uri>http://downloads.phoenixviewer.com/slvoice_os-4.6.0017.21209.500605-windows-500605.tar.bz2</uri>
+            </map>
+            <key>name</key>
+            <string>windows</string>
+          </map>
+        </map>
+      </map>
       <key>SDL</key>
       <map>
         <key>copyright</key>
diff --git a/indra/cmake/ViewerMiscLibs.cmake b/indra/cmake/ViewerMiscLibs.cmake
index 980b2a0fdc..5b55c557dc 100644
--- a/indra/cmake/ViewerMiscLibs.cmake
+++ b/indra/cmake/ViewerMiscLibs.cmake
@@ -8,6 +8,13 @@ if (NOT USESYSTEMLIBS)
   endif (LINUX)
   use_prebuilt_binary(libhunspell)
   use_prebuilt_binary(slvoice)
+  # <FS:Ansariel> FIRE-22709: Local voice not working in OpenSim
+  if (OPENSIM)
+    if (WINDOWS)
+      use_prebuilt_binary(slvoice_os)
+    endif (WINDOWS)
+  endif (OPENSIM)
+  # </FS:Ansariel>
 #  use_prebuilt_binary(libidn)
 endif(NOT USESYSTEMLIBS)
 
diff --git a/indra/newview/llvoicevivox.cpp b/indra/newview/llvoicevivox.cpp
index 8bebcb058d..26df5713f8 100644
--- a/indra/newview/llvoicevivox.cpp
+++ b/indra/newview/llvoicevivox.cpp
@@ -812,6 +812,14 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
         std::string exe_path = gDirUtilp->getExecutableDir();
         exe_path += gDirUtilp->getDirDelimiter();
 #if LL_WINDOWS
+        // <FS:Ansariel> FIRE-22709: Local voice not working in OpenSim
+#ifdef OPENSIM
+        if (!LLGridManager::instance().isInSecondLife())
+        {
+            exe_path += "voice_os" + gDirUtilp->getDirDelimiter();
+        }
+#endif
+        // </FS:Ansariel>
         exe_path += "SLVoice.exe";
 #elif LL_DARWIN
         exe_path += "../Resources/SLVoice";
@@ -831,7 +839,7 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
             // vivox executable exists.  Build the command line and launch the daemon.
             LLProcess::Params params;
 
-			// <FS:ND> On Linux the viewer can run SLVoice.exe through wine (https://www.winehq.org/)
+            // <FS:ND> On Linux the viewer can run SLVoice.exe through wine (https://www.winehq.org/)
             params.executable = exe_path;
 
             if( !viewerUsesWineForVoice() )
@@ -842,7 +850,7 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
                 params.args.add( exe_path );
             }
             //</FS:ND>
-			
+
             std::string loglevel = gSavedSettings.getString("VivoxDebugLevel");
             if (loglevel.empty())
             {
@@ -858,12 +866,12 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
                 log_folder = gDirUtilp->getExpandedFilename(LL_PATH_LOGS, "");
             }
 
-			// <FS:Ansariel> Strip trailing directory delimiter
-			if (LLStringUtil::endsWith(log_folder, gDirUtilp->getDirDelimiter()))
-			{
-				log_folder = log_folder.substr(0, log_folder.size() - gDirUtilp->getDirDelimiter().size());
-			}
-			// </FS:Ansariel>
+            // <FS:Ansariel> Strip trailing directory delimiter
+            if (LLStringUtil::endsWith(log_folder, gDirUtilp->getDirDelimiter()))
+            {
+                log_folder = log_folder.substr(0, log_folder.size() - gDirUtilp->getDirDelimiter().size());
+            }
+            // </FS:Ansariel>
             params.args.add("-lf");
             params.args.add(log_folder);
 
@@ -874,20 +882,19 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
                 params.args.add(shutdown_timeout);
             }
 
-			// <FS:Ansariel> Voice in multiple instances; by Latif Khalifa
-			if (gSavedSettings.getBOOL("VoiceMultiInstance"))
-			{
-				S32 port_nr = 30000 + ll_rand(20000);
-				LLControlVariable* voice_port = gSavedSettings.getControl("VivoxVoicePort");
-				if (voice_port)
-				{
-					voice_port->setValue(LLSD(port_nr), false);
-					params.args.add("-i");
-					params.args.add(llformat("127.0.0.1:%u",  gSavedSettings.getU32("VivoxVoicePort")));
-				}
-			}
-			// </FS:Ansariel>
-
+            // <FS:Ansariel> Voice in multiple instances; by Latif Khalifa
+            if (gSavedSettings.getBOOL("VoiceMultiInstance"))
+            {
+                S32 port_nr = 30000 + ll_rand(20000);
+                LLControlVariable* voice_port = gSavedSettings.getControl("VivoxVoicePort");
+                if (voice_port)
+                {
+                    voice_port->setValue(LLSD(port_nr), false);
+                    params.args.add("-i");
+                    params.args.add(llformat("127.0.0.1:%u",  gSavedSettings.getU32("VivoxVoicePort")));
+                }
+            }
+            // </FS:Ansariel>
 
             params.cwd = gDirUtilp->getAppRODataDir();
 
@@ -900,7 +907,7 @@ bool LLVivoxVoiceClient::startAndLaunchDaemon()
             params.args.add("-ch");
             params.args.add(LLVivoxSecurity::getInstance()->connectorHandle());
 #           endif // VIVOX_HANDLE_ARGS
-			} // <FS:ND/> 
+            } // <FS:ND/>
 
             params.postend = sGatewayPump.getName();
             sGatewayPump.listen("VivoxDaemonPump", boost::bind(&LLVivoxVoiceClient::callbackEndDaemon, this, _1));
diff --git a/indra/newview/viewer_manifest.py b/indra/newview/viewer_manifest.py
index cdcc89e557..6bc3903438 100755
--- a/indra/newview/viewer_manifest.py
+++ b/indra/newview/viewer_manifest.py
@@ -804,6 +804,20 @@ class WindowsManifest(ViewerManifest):
                 self.path("msvcp120.dll")
                 self.path("msvcr120.dll")
 
+        # <FS:Ansariel> FIRE-22709: Local voice not working in OpenSim
+        if self.fs_flavor() == 'oss':
+            with self.prefix(src=os.path.join(relpkgdir, 'voice_os'), dst="voice_os"):
+                self.path("libsndfile-1.dll")
+                self.path("ortp.dll")
+                self.path("SLVoice.exe")
+                self.path("vivoxoal.dll")
+                self.path("vivoxplatform.dll")
+                self.path("vivoxsdk.dll")
+                self.path("zlib1.dll")
+            with self.prefix(src=pkgdir, dst="voice_os"):
+                self.path("ca-bundle.crt")
+        # </FS:Ansariel>
+
         if not self.is_packaging_viewer():
             self.package_file = "copied_deps"