I think you are confused about what is being claimed. Jeremy Siek (the author) published two papers last decade: "Gradual Typing for Functional Languages" (htt

I think you are confused about what is being claimed. Jeremy Siek (the author) published two papers last decade: "Gradual Typing for Functional Languages" (http://www.cs.colorado.edu/~siek/pubs/pubs/2006/siek06:_gradual.pdf http://www.cs.colorado.edu/~siek/pubs/pubs/2006/siek06:_grad...) in 2006 and "Gradual Typing for Objects" (http://ecee.colorado.edu/~siek/gradual-obj.pdf http://ecee.colorado.edu/~siek/gradual-obj.pdf) in 2007. Those papers are not saying "we're the first to combine static and dynamic typing." Those papers are saying "we're the first to formalize the combination of static and dynamic typing into an overall sound type system."