It's not really a local speech pattern thing it has more to do with associating <product name> with <name of tool>. If you can think of examples for a dozen other traditional products (kleenex, ketchup, jello, aspirin..) it shouldn't be hard to imagine that people do it for gmail and technology products/services. It's also certainly not unheard of though it is still less popular than traditional "emailed" https://trends.google.com/trends/explore?date=all&geo=US&q=h...