The "L" and "N" that these British Columbians are talking about are the equivalent to the graduated licensing programs in many of the states, such as Washington. They also refer to these big magnetic letters that you have to put on the back of your car when you drive to signify that you are a new driver.
When I see them on the road, I think Loser:
Basically, they're a warning to other motorists that the person driving is even worse than the other BC drivers. Beware!
L is for learners, you must have a fully licensed person over 25 yrs old in the car. Unlimited passengers as long as you have a fully licensed person over 25 with you. You can take your N (New) exam a year later (I think), by passing that, you can drive alone with up to one unrelated passenger and unlimited immediate family members. If you have a fully licensed driver over 25 yrs with you, you can drive anyone. And then you get your class 5 (normal drivers license, goes up to 1 which I think is ambulance), which means you're unrestricted essentially for typical driving. No motorcycles, airbrakes, etc yet.