Greetings to the Children of England

"I can truthfully say to you all, that we children at home are full of carefulness and courage. We are trying to do all that we can to help our gallant sailors, soldiers and airmen. And when peace comes, remember, it will be for us, the children of today to make the world of tomorrow a better and happier place."

-Princess Elizabeth and Princess Margaret October 13, 1940

This was broadcast on the BBC Children's hour. Princess Elizabeth, age 14, was speaking to the British children, mainly those of Commonwealth, who had been excavated abroad about life back in England. The speech was made at the height of the Battle in Britain, and was broadcast to both the Children of Empire and to the United States.

It is clear that the speech is targeted towards children, for it is broadcast by a child and continuously encourages the viewers that "us children" will make a difference. Though the speech is talking about the unpleasant experiences that many children have had to face, it also emphasizes the hopefulness of the future and the help that they have received so far.

Emphasized words or phrases:
All
Carefulness and Courage
Home
We
Us
Tomorrow

Pauses:
The most prominent pause is between each word in the phrase "gallant, fearless, soldiers and airmen." This is probably due to the younger audience.
There is also a long pause after "it will be for us," emphasizing the hope for the future situation of the children of England.

Tone:
The whole tone of the speech is very calming and friendly, Princess Elizabeth makes you feel secure, even in the turmoil. Furthermore, at the end of the speech you can picture Princess Margaret joining her sister and holding hands to wish the children goodnight and good luck.

Full Speech:
http://www.telegraph.co.uk/news/newstopics/theroyalfamily/4590836/First-speech-of-Princess-Elizabeth-the-future-Queen-to-be-broadcast.html
You can listen to the entire speech at this link. It tells more background about the situation of the time.

Queen Elizabeth II
Elizabeth II (born 1926) became queen of Great Britain and Ireland upon the death of her father, George VI, in 1952. She was a popular queen who was also respected for her knowledge of and participation in state affairs.

Elizabeth II was born on April 21, 1926, in London, the oldest child of the Duke of York and his wife, Elizabeth. Her father became King George VI, of Great Britain and Ireland in 1936 when his older brother Edward VIII abdicated the throne. Elizabeth married Philip Mountbatten in November 1947, and they had four children - Prince Charles, Princess Anne, Prince Andrew, and Prince Edward.

Elizabeth II is one of the longest-reigning British monarchs ranking behind Victoria (who reigned over the United Kingdom for 63 years), George III (who reigned over Great Britain for 59 years), and James VI (who reigned over Scotland for 57 years).

WWII:
Within two months, World War II broke out. She and her younger sister stayed at Balmoral Castle, Scotland, from September to Christmas 1939, until they moved to Sandringham House, Norfolk. In May 1940, they moved to Windsor Castle, where they stayed for most of the next five years. There was some suggestion that the two princesses be evacuated to Canada, where they, along with their parents, would have lived at Hatley Castle in British Columbia. This plan never came to fruition; to the proposal, Elizabeth's mother made the famous reply: "The children won't go without me. I won't leave without the King. And the King will never leave."[20] The children remained at Windsor, where they staged pantomimes at Christmas, to which family and friends were invited, along with the children of Royal Household staff. It was from Windsor that Elizabeth, in 1940, made her first radio broadcast during the BBC's Children's Hour, addressing other children who had been evacuated from the cities.