General Prajna and Specific Prajna
The first dichotomy in kinds of prajna is that the Buddha taught general prajna to people with duller karmic roots, and specific prajna to people with sharper karmic roots. People with duller roots include shravakas (people who have heard the Dharma), as well as those already on the bodhisattva path. For them, the Buddha taught liberation methods like The Five skandhas and The Twelve Links (nidanas) of Dependent Origination.1 Of course, since we are ordinary beings with duller roots, this general prajna is good for us. For those with sharper roots, Buddha taught specific prajna. It is important to remember, however, that specific prajna always includes general prajna.
I will give an analogy to explain the difference between general and specific prajna. I recently read about a sixteen-year-old boy who has already earned his doctorate and is ready to teach in a university. Does this young boy with a Ph.D. also have the Knowledge of an elementary school, a high school, and a college student? If this is an appropriate analogy, then you can see that this boy has both the general knowledge of all his education, as well as the specialized knowledge associated with his degree. Would you say that this boy has sharp intellectual roots?