You know this. In common time a dotted quarter is the equivalent of three eighth notes tied together, a dotted half, three quarters tied. Why, though, dotted rhythms rather than even notes. Dotted notes speak of urgency, sometimes muted, sometime overt. When singing that dotted quarter in common time, let the third and tied eighth have a visceral interior pulse that launches you into the next note or notes. Insomuch as it is true than you cannot move unless first your are moved, this device can prove to be an important part of that.