writing function , giving input and printing them with a condition

I want to write a function, which will accept parameter and it will print with a condition (It's output will depend on the input). My program is giving key error. I am looking for an output like:

This number is less than 0 and it's spelling is one hundred

thirteen

and my code is:

def word(num):
   d1= {0:'Zero',1:'One',2:'Two',3:'Three',4:'Four',5:'Five',6:'Six',7:'Seven',8:'Eight',9:'Nine',10:'Ten',11:'Eleven',12:'Twelve',13:'Thirteen',14:'Fourteen',15:'Fifteen',16:'Sixteen',17:'Seventeen',18:'Eighteen',19:'Ninteen',20:'Twenty',30:'Thirty',40:'Fourty',50:'Fifty',60:'Sixty',70:'Seventy',80:'Eighty',90:'Ninty'}

   if (num<20):
      return d1[num]
   if (num<100):
      if num % 10 == 0:
         return d1[num]  
      else:
         return d1[num // 10 * 10] + ' ' + d1[num % 10]
   if (num < 0):
      return "This number is less than 0 and it's spelling is" + word(num)

print (word(- 100))
print (word(13))