Word Muddling in AS?

I thought it would be cool to try and make a translator/word muddler based on this pic:

The user types some text into a textbox and it gets “translated” into another.

I have no idea where to start. Maybe I need to use an array and put each letter in and then return them tin a different order? (I have never used an array before)

Is this too tricky for my limited AS knowledge?

Thanks