Can someone explian why Churchill and King George VI both delivered a speech in the face of ww2?

Not sure what you are getting at, but the King is the Head of State and (particularly at the time of WW2) was an important symbol for the British people. On the other hand, Churchill was the Prime Minister and head of the Government. His influence was immense in encouraging the Brits to dig in and resist the Germans. Unlike the US today, where politicians are largely ignored both the King and the PM had an important role in leading the British (for actual speeches see the link). But as I say, I'm not sure what your point is.