If a new version of Crew Chief is available the auto updater will prompt you to download it. This will download and run a new .msi installer - just point it at the existing install location and it'll update your old installation. It won't remove your existing sound pack or your settings.
If a new sound pack or driver names pack is available the appropriate Download button(s) will be enabled - these will download and unpack the updated sounds / driver names, then restart Crew Chief.
The 64bit speech recognition installers can be downloaded here
The 32bit speech recognition installers can be downloaded here