To use a Metapad language plugin simply download the appropriate file from this page and unzip it anywhere on your machine (c:\windows\system, c:\winnt\system32, metapad folder, etc.). Then run Metapad and select Options | Settings | Bufers & Language and click the "..." button in the Language box. Locate the plugin DLL file that you downloaded and unzipped and restart Metapad.
If the language you desire is not available above and you are interested in creating and maintaining a language plugin then review the plugin development documentation and send it to me.
What's New
Mar 20, 2016: Added Ukrainian plugin for Metapad 3.6
Aug 15, 2015: Added revised Catalan plugin for Metapad 3.6
Jul 14, 2014: Added revised French plugin for Metapad 3.6