premise: President Bush delivers a speech to a large audience. hypothesis: The president is speaking to a large crowd.
entailment: Sentence 2 is a more concise version of sentence 1. "President Bush delivers a speech to a large audience" sounds intelligent, but stilted and academic to the modern listener, while "The president is speaking to a large crowd" is warmer and more familiar. Someone writing a television script might write edit the first one into the second one.