I was going to post similar information, since just last week I discovered that this was his son. For years, anytime I googled Harry Langdon, I would see a photographer's name come up -- I don't think it always said "Jr.", so I thought it was just someone with the same name.
Last week was the first time I dug in and discovered who he was! It's fascinating, and I did watch an interview, and read one too, but not one of the ones you posted. Since he said Laurel and Hardy were frequent visitors to his house, I said to myself that he really needs to document his memories of the boys, too (if he hasn't already.) But since Harry, Sr.,died when he was only 10, I'm sure the memories are a bit blurry. It was fascinating to read that he did many photo sessions with Sinatra, too. Sinatra and Langdon -- whoda thunk it?
I'm surprised that TCM didn't have him on the show introducing his Roach talkies when they showed them way back when.
They had W.C. Fields' granddaughter on when they had a min-Fields marathon.
