Apparently she changes shoes once she is at the event. Some pages back I commented on those shoes and then saw Pictures inside which showed her in different shoes.
It seems a tad weird, considering that she doesn't take the commuter train, but has a car waiting for her which most likely is ready to go with the heating on. If it was me, I might change out of the uncomfortrable high heels into some cosily warm Ugg-style booties once inside the car or perhaps fat socks…
As to her german: I have heard her speak german and while apparently she isn't completely fluent with a big vocabulary, her accent is great and her grasp of the language very well indeed - much better for ex. than fellow half german Willem Alexander..