People speaking on their charity.
Some people speaking on their charity.
'People' is already vague enough; 'some' people draws no additional conclusions and modifies no information.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_charity(x3) & of(x3,x1) & n_thing(x1) & Actor(e1,x2) & v_speak(e1) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_charity(x3) & of(x3,x1) & n_thing(x1) & Actor(e1,x2) & v_speak(e1) & (x1 = x2) & n_people(x1))