[ninlaith]

Yes the ring does shrink. Or more like the person that holds the ring imagines the ring shrinking so they can have control. But really it has control over them. And as Eomer pointed out the ring does speak. It has a voice for every person tempted by the ring. For example Aragorn, the ring calls him Elessar...a name of power and truth... the ring has a very sweet seductive tongue when it speaks to him. With Frodo it's more of a disheartening black speech that wishes to overtake the naive young hobbit...and it knew it could easily in time. Then Boromir...a very menacing voice of black speech....a voice of brutal, hideous power....almost as if saying to him "You could have this power...take the ring!!" PJ does a little explanation about the voice and the rings "shrinking" on the extended edition.