speechifier       
noun [ C ]  informal disapproving uk/ˈspiː.tʃɪ.faɪ.ər/ us/ˈspiː.tʃə.faɪ.ɚ/
 发言令人厌烦或煞有介事的人
a person who gives a speech or speeches, especially in a boring way or in a way that shows they think they are important
  At the awards ceremony, he was among the best of the many speechifiers. 颁奖典礼上有众多乏味的发言者,他属于说得最好的几个之一。 
 - More examples
 - Andrew is the speechifier in the family, and he may talk too much for the play's good.
 - The grand speechifier was reduced to utter panic and speechlessness.
 - It is a mistake to believe that Robespierre was a speechifier in love with general ideas and adept only at phrase-mongering and theories.
 - He was both a speechifier and a prolific writer.