In 1952 she would have been heard referring to "thet men in the bleck het". Now it would be "that man in the black hat". Similarly, she would have spoken of the citay and dutay, rather than citee and dutee, and hame rather than home. In the 1950s she would have been lorst, but by the 1970s lost. And indeed, the Queen's first Christmas broadcast was pure Dartington Crystal. She began: "As he (King George VI) used to do, I em speaking to you from my own hame, where I em spending Christmas with my femly."
She has become definitely less upper class — dropping an octave and coming nearer to her own "Queen's English", by which I mean nearer to standard English. There have always been variations in royal speech. The Queen Mother was the embodiment of the upper class lady in the first class compartment, while George V was more like a hoarse country gentleman. Edward VIII adopted a kind of upper class cockney, talking of "moi house", but after his marriage began to sound more American.
About two or three years ago I was sitting next to the Queen at tea and she remarked that some of her grandchildren talked Estuary. I think she was talking about the Phillips children — but then Princess Anne always sounded a little suburban. And then there's Prince Edward, who sounds a bit Estuary — whereas the Dukes of Kent and Gloucester are proper country gents.