同学你好，该知识点来自沪江网校《英语零基础直达大学六级【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
speak 用来指人们对语言的掌握或使用，也可单独用来表发言或说话的基本能力。后面跟人做宾语要加介词 to, speak 作及物动词时后面跟各种语言
She can speak English very well.  
to speak in public公开演讲

say是最普通的用语，着重指说话的内容。及物动词
He said he would say something at the meeting.  

talk 一般用作不及物动词，着重指连续地说话或与人交谈。是不及物动词, 后面跟人的时候用介词with、to 等, 后面跟“事情”要用到介词about
I shall talk to your father about your health.  
talk about 谈论……，what you are talking about 你在谈论什么，你在说什么
He can't bear to talk about it, even to me.
他不想和别人谈论这件事，哪怕对我也是一样。

tell的意思是“告诉”，“讲述”，“吩咐”。是及物动词, 后面首先要跟人, 然后再跟从句或者介词短语等。
She told me her name.  

祝同学学习进步~