whether you like it or not, how somebody speaks greatly effects both how we feel about them and how the world feels about them. A good public speaker can shake the world and shape history. Think about some of the great speaches, the whole ask not what your country can do for you thing, Martin Luther King Jr. with the I have a dream speach, the list goes on and on. These people were viewed and remembered as heroes. What do we remember from dubya?
"fool me once, shame on, shame on you, fool me twice shame on, well we cant get fooled again" and "to many good docs are going out of buisness, to many obgyns arent able to practice their love all across the nation." and my favorite "nelson mandella is dead... (gasps in the audience) what I mean to say is that there are no mandellas in iraq, saddam killed them all"
so yes, public speaking skills are very important when it comes to how other countries view us