Question: What is Mourner's Kaddish?
Answer: The Mourner's Kaddish, one of a few types of Kaddish prayers, expresses the mourner's love of God and acceptance of God's will, even while the mourner is feeling great loss and sorrow over the death of a loved one.
A minyan, ten Jewish adults (male only, in orthodox congregations), is required for reciting the Kaddish. The Mourner's Kaddish is recited by children (sons only, in orthodox congregations) for their parents for eleven months, and by immediate family for a brother, sister, son, daughter and wife for thirty days. The Mourner's Kaddish is also recited on the anniversary of the death of the mourned family member.
The prayer, which begins with "Magnified and glorified is His great name", is an ancient Aramaic poem. The last line, however, is Hebrew and comes from the Book of Job - "May He who makes peace in high places make peace for us and for all Israel. Amen." When reciting this last line, the mourner takes three steps back as if he/she is concluding his/her "audience" with God and retreating respectfully.