For giggles I tried writing this in Oz. The ReverseWords function could have been written without all the intermediate variables but it would have suffered in readability so I didn't. It's also a complete program with loading the appropriate libraries, etc.

functor
import
   Application
   System
   String at 'x-oz://system/String.ozf'
define
   fun {IsntNil X}
      case X of nil then false
      else true
      end
   end
   fun {ReverseWords In Split}
      local Tokens FilteredTokens Reversed Str in
         Tokens = {String.split In Split}
         FilteredTokens = {List.filter Tokens IsntNil}
         Reversed = {List.reverse FilteredTokens}
         Str = {String.join Reversed Split}
         {String.toAtom Str}
      end
   end
in
   {System.print {ReverseWords "  one   two three four    " " "}}
   {Application.exit 0}
end
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