I am hearing more incidences of people being asked a direct question responding with a reply beginning with
So, ...
For example,
Questioner: "What do you think we should buy Janice for her birthday present?"
Respondent: "So, I thought that a voucher towards the cost of a meal for 2 at an expensive restaurant would be good, but with the Covid lockdown, I don't know when she would get any use out of it."
When, where and how did this enter into the English Language?