[infotropy]

As the word changes, do the green letters I may have gotten always remain green? They remain valid letters and always stay in the same location?

[JacobAldridge]

Just played a few games - and No, they don't, though it will tell you (for example) 'S changed to G' which means that G is now in the same place the 'S' was ... unless there were two Ss of course!

[ralusek]

Exactly right. Thanks for answering