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How are you trying to debug the code? Add some print statements in all the methods that print out the values they receive and return.
Also print out the values of the variables used in the loop in...

The comments are too thin. For example:
What is in the String that the method returns?
How does the code build the String that is returned?
What values are in the variables: word, phrase and...

Can you add some comments to the code describing what each method is supposed to do?