>>9
PLT Scheme is pretty dynamic and also pretty fast compared to Python, Perl, Ruby, Smalltalk, PHP. Psyco comes close, as does Lua. Faster are LuaJIT, Steel Bank Common Lisp (is it really dynamic/still faster when dynamic?), Scala (thanks to the JVM).
Disclaimer: based on shootout results.
So while dynamic Scheme might not be the fastest, it's certainly
not SLOW AS FUCK.