Male standing at a podium speaking.
A male is performing a speech at a graduation.
You don't know in the first sentence where he is speaking, so you can't infer that it's at graduation.
exists s1 x1 x2 x3.(a_topic(x1) & at(x1,x2) & n_speaking(x2) & of(x2,x3) & n_podium(x3) & n_standing(x1) & a_male(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(at(e1,x3) & n_graduation(x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_speech(x2) & n_male(x1))