After awhile it became undisciplined rambling
It also demonstrated why the Democratic Party ousted their nominee. There’s no why he could have campaigned until November 5th in this condition.
Several times during the speech when Biden lost his place or began to slur his words, the delegates bailed him out by cheering, applauding, or chanting. This bought him time to refocus on the teleprompter and resume his messed up speech.