nice old post by Duilio Tacconi.
“In this blog post you will find the source code (below) to “let NAV speak.” You would have a wide range of possibilities to use this simple Add-in and enlarge this project.
If you want to know more about Client Add-ins you can refer to this MSDN link:
Extending the RoleTailored Client Using Control Add-ins and Microsoft Dynamics NAV 2009 SP1
This simple Client Add-In is based on System.Speech namespace:
Microsoft.Speech.Synthesis Namespace
Source: Let NAV Speak (with a Simple and Useful Client Add-in) – Dynamics NAV Team Blog