replace vowels

[ichabod801]

That is not really what I suggested. I suggested two loops, one of the words in the list, one over the letters in vowels. I also suggested using replace to replace the vowels, and only appending to new_list after the loop over vowels is done (actually, I may have misstated that last part, but that's what it should be). Look at these lines:

for letter in mlist:
    if letter in vowels:

mlist is a list of words (names, really). So why would you call the loop variable 'letter'? And why would a whole name be in vowels?