My navi language is polish. It was my first trip with OSM navi. Map alone was great, full cover, but when i've heard turn left in polish on the highway... hmm :) i think it would be better to add "keep on the lef side of the road/left lane" instruction, than just turn left for everything...
i was driving with a car, route was created for best speed... on my vordon navi...
This happened on the A12 highway part, more than once... so if You check please look there, rest of the route was great... Of course map itself was showing good direction of the highway, only voice command should be a bit different.