Because SetNatTx is such a simple program, I am also posting the source code.  The program is written in C++.  If you want to compile the program yourself, you will need both the C++ file and the DEF file which tells Windows which functions to export.

(You do not need this source code to use SetNatTx or to understand how it works.)

---------------------------------------------setnattx.cpp---------------------------------------------
#include <windows.h>
#include <stdio.h>

extern "C"
int APIENTRY DllMain( HINSTANCE, DWORD, LPVOID )
{
   return 1;   // ok
}

extern "C"
int WINAPI SetNaturalText( LPSTR pszState )
{
   HKEY hKey;
   HRESULT rc;
   BOOL bSet;

   bSet = ( *pszState == '1' || *pszState == 't' ||
            0 == stricmp( pszState, "on" ) );

   rc = RegOpenKeyEx(
       HKEY_LOCAL_MACHINE,
        "Software\\Dragon Systems\\NaturalText",
       0, KEY_WRITE, &hKey );

   if( rc == ERROR_SUCCESS )
   {
       rc = RegSetValueEx(
           hKey, "Enable Global Dictation", 0, REG_SZ,
           (const BYTE *)( bSet ? "1" : "0" ),
           2 );
   }

   if( rc != ERROR_SUCCESS )
   {
       char szBuffer[ 256 ];
       sprintf( szBuffer,
           "Unable to access the Dragon NaturallySpeaking registry"
           " (code = 0x%x)\r\n\r\nThis utility will only work with"
           " Dragon NaturalText Version 2.",
           rc );

       MessageBox(
           0, szBuffer, "SetNaturalText Error",
           MB_ICONWARNING | MB_OK );
   }

   return 0;
}

---------------------------------------------setnattx.def---------------------------------------------
LIBRARY      SetNatTx
DESCRIPTION  'Change the state of NatutalText'

SECTIONS

EXPORTS
   SetNaturalText    @1
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