[plt-scheme] Why do folks implement *dynamically* typed languages?

> I suppose it could be called that.  DO you know languages that actually 
> do this?

In the literature:

     http://www.citeulike.org/user/dherman/tag/type-dynamic

In history:

     Modula-3 (type REFANY)
     Amber (type dynamic)
     Quest (type Dynamic_T)
     VB (type Any)
     Cecil (type dynamic)
     Typed Scheme (implicit)
     ECMAScript Edition 4 (type *) <-- proposed

Dave