It is used as a vegetable in the sour soup called sinigang and it is cooked like sweetened fruit in the snack called guinataan. It is called taro but Filipinos know it by its local name, gabi. In Sri Lanka, it is called kiri ala; in Malaysia, the name is keladi; in Thailand, phueak; in Vietnam, khoai mon; and in Japan, sato-imo (source: Asian Food by Charmaine Solomon).
The popularity of yam extends beyond Asia and into the Pacific where it is found in the cuisines of Hawaii and many Polynesian islands. It is also called arrow root in some cultures. If you see a recipe that uses arrow root to thick a broth or sauce, it is yam that is being referred to except by another name.
The yam consists of the edible root — or corm, to be more precise. The taro leaves are eaten as a vegetable usually with coconut milk (more on taro leaves in a separate entry).
The yam must be peeled before cooking then cut according to the desired size and shape. Once cooked, the yam releases its starch making it sticky. And the longer it is cooked, the starchier and stickier it becomes.