As an abbreviation, it can stand for litre. Also, a sign on a car with a Lamed on it means that the driver is a student of driving (the Lamed stands for lomed, learner).
As a prefix, it can have two purposes:
It can be attached to verb roots, designating the infinitive (Daber means "speak", Ledaber means to speak).It can also act as a preposition meaning "to" or "for", Government. The Tzadikim Nistarim exemplify a mode of leadership that differs from the notion of the visionary public leader that scholars suggest is overvalued in modern culture, but is well encapsulated in the aphorism that Presidents Truman and Reagan cited, "There is no limit to what a man can do or where he can go if he doesn't mind who gets the credit".