Why do you say "this guy" instead of "a guy"? How different them?
Native speaker’s answer
Rebecca
In this video, she says "this guy" because she is telling a story and doesn't want to reveal who the person is. However, she could have used "a guy" in this sentence and it would have made sense. I believe she uses "this guy" as a way of being more specific whereas "a guy" is more generalized. Ex: There was this girl at camp who was an amazing swimmer. Ex: When I was at the grocery store, there was this couple who were yelling at a cashier. It was ridiculous. Ex: 'I Am Malala' is this amazing book about a girl who stood up against the Taliban.