Complex sentence: He is a top scholar in the field of Western academic Buddhism, though he admits that he doesn't have Walpola Rahula's depth of understanding of the Pali Canon-few Westerners do.
Split into simpler sentences: He is a top scholar in the field of Western academic Buddhism. He admits that he doesn't have Walpola Rahula's depth of understanding of the Pali Canon-few Westerners do.