🚀 go-pugleaf

While this newsgroup seems to cover many research languages, I would like
to mention one that is used by an awful lot of people:  dBASE

You don't need to declare types of variables/functions/parameters, and arrays
can be polymorphic with each element being a different type.

For example, you can write a function as follows:
  function addtwo
    parameters a,b
    return a+b

If you call it as  addtwo(1,2)  you get the result 3.  If you call it with
addtwo("abc","def")  you get the result "abcdef".

As for arrays, you can do something like this:
  dimension arr[5]
  arr[1] = 1
  arr[2] = 1.23
  arr[3] = "abc"
  arr[4] = .f.    (boolean values)
  arr[5] = ctod("09/07/61")   (date values)

While many implementations of the language are interpreters, some are 
compilers. (for DOS, Mac, Unix, Vax, etc.)

So, you see, polymorphism isn't such an ivory tower topic.