At least 95% of people phrase the first line of Kaddish incorrectly.
Most people say:
“Yisgadal V’Yiskadash Sh’mei Raboh, B’alma Di V’ra Chir’useih V’Yamlich Malchuseih…”
The correct phrasing of the first line is:
“Yisgadal V’Yiskadash Sh’mei Raboh B’alma Di V’ra Chir’useih (COMMA!!) V’Yamlich Malchuseih…”
(Granted, we say Amen in the middle of the line, but it should still be phrased correctly)