Are you asking what programming languages can be used for VEGAS Script API?
In general, you should use C# based on .NET Framework. Some other programming languages, such as JScript (not JavaScript) and Visual Basic, can also be used, but they're deprecated and only used by old scripts.
@Mooreasys Strongly suggest going through all the jetdv tutorials which nicely cover Vegas api programming both with stand-alone scripts and compiling to a DLL using the free Visual Studio development platform. VS is your gateway to using any language it supports from C# down to Assembly Language.