Answer 1

Easiest way to do things like this is just list out the steps of how you want the program to run on paper. I'm no expert in this in particular, but you could simply (note: not the best way) use a dictionary and a text-parsing program.

1. Needs to be able to read a file that you select. So basically ask for filename as input.

2. Read each word. You could convert the whole text file into a string and the separate it into items in an array using the space as a separator.

3. Search for each item in the array in your dictionary (could be another array) and compare. If it is there, move on, if not, alert the user somehow.

This is clearly not how Microsoft Word does it. This would be terribly inefficient, but it's a starting point. As you get more experienced you will write all kinds of algorithms to make things better than this. Good luck.