Know that what is meant by the small letters is the three movements, which are the dhammah, the fatha, and the kasra. These letters have two states, a state of saturation and a state of non-saturation. If one of them is characterized by saturation, it is a reason for the presence of an effect that matches it. If the dhammah is saturated, it is caused by the waw, and if it is a fatha, it is caused by an alif, and if it is a kasra, it is caused by it. The effected yaa, but we restricted the waw and yaa to the cause because they may exist in the position of validity without being described by the cause, and the alif never exists except as an effect, and therefore what comes before it is never anything but open.