hasher

def classify(o)
  case o
  when Hash
    h = {}
    o.each {|k,v| h[k] = classify(v)}
    h
  else
    o.class
  end
end

p classify({'en' => {'A' => 1, 'B' => {'C' => 3, 'D' => 'four'}}})

Output:
{"en"=>{"A"=>Fixnum, "B"=>{"C"=>Fixnum, "D"=>String}}}