请问speak,talk,say他们有什么区别?

请问speak,talk,say他们有什么区别?
还有see和watch的区别,

Speak,Talk,Say和Tell
Speak比较庄重,表示某人(即讲者)在一段对话中所说的话较其它人多.
举例：
The Principal speaks to us every morning at the assembly.
Tom,your boss wants to speak to you.
Talk不及speak庄重,而且多用于说话,少用于书写.Talk表示两个或更多的人在对话.
举例：
The students were talking loudly in the classroom,in the very presence of the teacher.
当宾语是一种语言时,要用 speak 不用 talk 或 say：
正确：Victor speaks fluent Putonghua.
错误：Victor talks fluent Putonghua.
错误：Victor says fluent Putonghua.
在书面英语,talk 极少用作及物动词,除非在 talk 后接用以下的宾语：
Stop talking nonsense.
They are talking business again.
若不是接用上列的宾语,talk 后必需接用前置词 about.
举例：
正确：Betty and Susan are talking about the trip to London.
错误：Betty and Susan are talking their trip to London.
Say通常跟讲者所说的话一起使用,不论是直述句或陈述句：
Please say hello / thank you to your mum.
What did your father say when you told him about your plan to get married?'I cant believe it,' he said.
He said that he could not believe it.
可是,say 有时也可用于一些非直述句或陈述句中.
看看以下的例子：
I want you to say something about how we met at our wedding party.
注意 something about how we met并不是用于引述别人所说的真实语句.
另一方面,tell 并不是用于引述别人所说的话语,而是表达别人的说话中所述的事实或资料：
He told me about the accident.
He told his parents the truth.
He told us a funny story.
see的意思是“看见”、“看到”,通常指不知不觉地通过视觉看见物体,可能是有意识地看也可能是无意识地看,着重强调看（look）的结果.see可用作看电影,看戏剧.例如：
It was clark and we couldn’t see anything．
Are you going to see the film this evening?
watch的意思是“观看”、“注视”,强调注意力的集中,常指有意识地注视正在发生或将要发生的事情,后面跟的宾语往往是正在活动的人或物.例如：
We are watching TV now．
Are you going to watch the football match．