Hi Again,
It looks there is at least one place in your code where you have SentAfterPrac.split() rather than SentAfterPrac.split(" "). This is probably why you get the whole sentence displayed rather than individual words in succession.
The TypeError .split is not a function that you are getting typically means that SentAfterPrac is not a string. So I would check the file that loads this variable and see how the trial that elicits this error might be different from the others.
Good luck!
Keith