$KCODE = 'u'

ruI18n = {
  'test1' => 'тест1',
  'test3' => 'тест3',
  'test4' => {
    'test5' => 'тест5'
  }
}

enI18n = {
  'test1' => 'test1',
  'test2' => 'test2',
  'test3' => {'test4' => 'test4'},
  'test4' => {
    'test5' => { 'test6' => 'test6' }
  }
}

Hash.class_eval do
  attr_accessor :general_value

  def mix_with other_hash
    self.merge(other_hash) { |key, oldval, newval|
      if oldval.class == String and newval.class == Hash
        newhash = Marshal.load Marshal.dump(newval)
        newhash.general_value = oldval
        newhash
      elsif oldval.class == Hash and newval.class == Hash
        oldval = oldval.mix_with newval
        oldval
      elsif oldval.class == Hash and newval.class == String
        oldval.general_value = newval
        oldval
      else
        oldval
      end
    }
  end

end

def general_value data
  if data.class == Hash
    if data.methods.include?('general_value')
      data.general_value
    else
      nil
    end
  else
    data
  end
end

# alias для general_value
def gv data
  general_value data
end

# выводит Hash на экран со всеми значениями
def print_hash hash, level=0
  tab = "    " * level
  hash.keys.each do |x|
    value = hash[x]
    if value.class == String
      puts tab+"\"#{x}\": \"#{value}\""
    elsif value.class == Hash
      if not general_value(value)
        puts tab+"\"#{x}\":"
      else
        puts tab+"\"#{x}\": \"#{general_value(value)}\""
      end
      print_hash hash[x], level+1
    end
  end
end

ruI18n = ruI18n.mix_with enI18n
puts "====================="
print_hash ruI18n
puts "====================="
puts "#{ruI18n['test1']}"
puts "#{ruI18n['test2']}"
puts "#{ruI18n['test3']}"
puts "#{ruI18n['test4']}"
puts "====================="
puts gv ruI18n['test4']
puts gv ruI18n['test4']['test5']
puts gv ruI18n['test4']['test5']['test6']