Magnified and sanctified be His great name in the world which He has created according to His will. May He establish His kingdom in your lifetime and during your days, and during the life of the whole House of Israel, even swiftly and soon; and say, Amen.
May His great name be blessed forever and to all eternity.
Blessed and praised, and glorified, exalted, extolled and honored, magnified and lauded be the name of the Holy One, blessed be He, though He be high above all the blessings and songs, praises and consolations which are uttered in the world; and say, Amen.
May He Who makes peace in His high places make peace upon us and upon all Israel; and say, Amen.
Since Kaddish makes no direct reference to the dead or to a hereafter, why did it become the prayer that mourners say? One explanation is that it is an expression by a bereaved person of his acceptance of the Divine judgment (tzidduk hadin). In a time of tragedy and loss, one might become bitter toward the Lord and reject Him. At precisely such a time, we rise to praise Him and publicly to affirm our belief in His righteousness. Kaddish reflects the mood of Job's declaration: “The Lord gave and the Lord took away, let the name of the Lord be blessed” (Job 1:21). It also reflects the verse from Psalms: “I found trouble and sorrow. But I called upon the name of the Lord ...” (Psalms 116:3-4
Source: Hayim H. Donin. To Pray As A Jew