Why is kaddish said for eleven months?
Death is the separation of the soul from the body. Following death, the soul goes through a purification process as it prepares for its new “life” in the purely spiritual realm. The more morally and spiritually refined one was while alive, the less purification is needed. The more morally and spiritually deficient one was, the more purification the soul will need. The longest this process can last is twelve months, and that is only for the souls of the most morally corrupt and spiritually debased people. Kaddish provides a spiritual benefit to the soul while it is undergoing purification. To say kaddish for twelve months would imply that the departed person lived the worst kind of life and is in need of the absolute greatest amount of purification. That is a judgment Jewish tradition does not make about anyone.
