I took the liberty to alter your code a tad bit, see below including the explanation.
pyg = 'ay'
original = raw_input('Enter a word:')
word = original.lower()
first = word
new_word = word[1:] + first + pyg
if len(original) > 0 and original.isalpha():
I personally like all the variables at the top, but you can do it however you please this just makes it easier for me. So first I got rid of new_word[1:] since we can just do new_word = word[1:] + first + pyg and it will do the exact same thing. Also notice I set print to new_word instead of original because you are wanting to print the final product not the original. That is pretty much all I changed you can do this multiple ways, but this way works best for me. I hope I helped you out if anything reply here.