לזכות ידי"נ הרה"ג ר' ישראל אפפעל שליט"א וכל אשר לו לברכה והצלחה עד בלי די!!
We say Kaddish in Aramiac so that the angels won't understand and don't become jealous of us. The Zohar Hakadosh [Mishpatim 105] connects this to the phrase of Yehoshua [7/9] והכריתו את שמנו מן הארץ ומה תעשה לשמך הגדול. - If our name is destroyed from the land then what will you do for Your Great Name?! Says the Zohar - That is why we say יתגדל ויתקדש שמיה רבא - Hashem's great name should become greater and sanctified.
According to this it seems that there is an עבודה to define ourselves as vessels of the glory of Hashem without having any other personal definition, otherwise the argument of Yehoshua "ומה תעשה לשמך הגדול - what will you do for your Great Name?!" has no validity. If it is about US - then we have no merit to be saved. It MUST be about Hashem's great name.
This can only be accomplished when we have a minyan of ten people for Kaddish.
We say Kaddish in Aramiac so that the angels won't understand and become jealous because they lack this quality of being vessels for the revelation of Hashem's name. On the contrary - they HIDE the glory of Hashem, as we see in מכת בכורות where it says אני ולא מלאך - Me and no angel, meaning that there was a revelation of Hashem's glory without the הסתר [hiddenness] that takes place when the angels are involved.
This is a HUUUUGE AVODA!!!! To think of ourselves as mere vessels of כבוד שמים!!!
Let us be equal to the task!.
[עפ"י ס' ואני תפילה עמ' י"ב]