Didn't hear that when I had my demo car, but I would be interested in knowing if anyone knows what actual voice is used. Is this the classic Samantha voice or something else (those in Interactive Voice Response will know well what I'm talking about (no pun intended)). In some GPS systems you can pick the voice you want (male/female/type), and Samantha is one of the most used as the default in EN/us (English/United States).
A roundabout-relevance to the OP: perhaps if if the country was set incorrectly, the 'accent' could sound like that, but that's a long shot.