Interesting. I will have to purposely go that way home tonight and watch the map. Wish it would speak it too."A" seems to be driven automatically by the system, as far as the shape of the intersection, and whether or not to give you guidance through it.
As for "B", when there's an actual turn, it'll tell you you're turning onto a different road. But if the road name simply changes, it's a mixed bag. 100% of the time, however, you'll see a blue bubble on the map alerting you that the name is changing. On some highways, it'll give you a voice alert.