By default SearchWP applies English stemming when enabled on the main SearchWP settings screen. This extension will instead apply Dutch keyword stemming when that option is enabled.
To install the SearchWP Dutch Stemmer, first download the plugin from the WordPress Plugin Directory. Once the plugin is downloaded, navigate to the WordPress Dashboard, click on Plugins, and then click on Add New. From there, click on Upload Plugin, choose the plugin file, and then click on Install Now. After the plugin is installed, click on Activate Plugin.