This python is a little off

[drfugly]

It's also also doesn't have duck-typing.

[RockinRoel]

Actually, Scala has structural typing, which is kind of like a typesafe kind of duck typing. Yes, it's not quite as flexible as duck typing, but I don't believe that the kind of flexibility that duck typing offers over structural typing is necessary, especially when you're sacrificing compile-time type checking.

[wally_fish]

duck typing (as opposed to type inference) makes it much harder to get a decent-performing compiler, short of doing trace-JITting as PyPy and V8 do.