Hi,
Please update to build 25.0.99 first. This build added voice recognition support. In order to use this feature you must:
1. Because voice recognition relies on Google Cloud API to function, you must configure your Google API key. See here for more details:
https://www.essentialobjects.com/doc/webbrowser/advanced/google_service.html2. Handle WebView.RequestPermissions event and call e.Allow() to allow the permission;
After these changes you should be able to use voice search.
Thanks!