If you refer to a long speech by one person during a conversation as a monologue, you mean it prevents other people from talking or expressing their opinions. 长篇大论
noun [具体名词]长篇独白,独角戏;长篇大论,滔滔不绝的讲话
His actions were accompanied by a rambling monologue. 他的行动伴随着一串冗长含糊的独白。
mono- = single 表示“单个,一个”monologue 独白(mono+logue 说话→一个人说话→独白)