Josh,
It doesn't look like you're doing anything with punctuation or capitalization. This is going to make your output look put together, but perhaps a bit more uninteresting (capitalized words always follow periods, but there are much less options).
It is legitimate to simply strip out punctuation and call ```.lower()``` on everything, or to try to do something more clever, but we would like to see you do some text processing to address this.
Thanks!