This question is pretty straight forward. Why do Jedi or Sith say something when they uses Force Persuade/Mind Trick? One example from Episode IV: "These are not the droids you're looking for." I know that Force users lift their arms and stuff to help them concentrate, but I don't think that speaking would work the same way, because they are not exerting very hard to persuade someone. Yoda in Episode II had to make a great effort to catch the pillar before it fell on Obi-wan and Anakin. Ben Kenobi isn't seen to need to make such a great effort in Episode IV.