The President was referring in particular to 1940, but Churchill's stimulating use of his native language was constant throughout his long and distinguished life.
Language has two forms, written and spoken.
Churchill was a master of both. As a journalist, essayist, author, novelist, historian, biographer, editor, correspondent, communicator, conversationalist and speaker he had few equals in any one of those fields, much less all of them. He has been described as a law unto himself in his use of words, as in so many other matters. Authors are the happy people in the world, whose work is pleasure. No one can set himself to the writing of a page of English composition without feeling a real pleasure in the medium in which he works, the flexibility and the profoundness of his noble mother tongue.