The plot of the story 

       "The Romance of a Busy Broker" has no introduction, it starts with an exposition, where the main characters (Pitcher - a confident clerk and Harvey Maxwell - a broker) and the place of the event (an office) are presented. 
       Then goes author`s narration with the development of the events. We see the author′s presentation of a busy broker′s day which consists of a chronic attack of buzzing of telephone, the thronging men in the office, the jumping clerks who are like the sailors during a storm. It is like hurricanes, landslides, snowstorms, glaciers and volcanoes but in an office. And during this crazy morning time Mr. Pitcher misunderstands his boss and call for a replacement stenographer to replace Miss Leslie . Until Mr.Maxwell finds out and gets upset, telling a clerk that Miss. Leslie will hold the job of stenographer until she can not anymore. 
       The story reaches its climax when lunch hour for the office comes around and Mr. Maxwell understands that he is in love with Miss. Leslie. He asks her to marry him and find out that they got married the pervious night at a small church around the corner from the office:

      "It's this old business that has driven everything else out of your head for the time. I was frightened at first. Don't you remember, Harvey? We were married last evening at 8 o'clock in the Little Church Around the Corner."

       There is no conclusion in this story and O. Henry lets the readers make it themselves.
       Talking about types of speech employed by the author -it is a mix of narration, description and insertions of dialogue.