I downloaded a tool called RegEx Coach. It has a free trial period but you may find you want to pay for it. When you highlight part of an expression it gives a plain English description. It's neat to work interactively with a tool like that while learning regular expressions.
One note: That particular tool is not 100% compatible with Java's regex. Plus you have to add escape characters in Java. Google for regular expression tools in Java for more. There is one that works as an Eclipse plugin if that sounds useful.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi