I've noticed a shift towards a form of speech that I would love to know more about. It first showed-up in US TV dramas I think, but now it's common to hear it used in everyday conversation.
Here are some examples:
"My sister, she came over for tea"
"My father, he drove the car"
"Her friends, they came to her birthday"
"The sun, it is bright"
and common in US TV crime dramas, something like:
"The murderer. He dropped the gun."
Why did people stop saying "my sister came over for coffee" and started including the pronoun ?
(also, questions ending in "how" or "why" -- why ?)