1. tell 意为“告诉、讲述”，指某人把某一件事、一条信息传送给别人或讲述一件事。如：
He tells me that he wants to be a teacher.
Father always tells interesting stories to us.
tell sb sth 意为“告知某人某事”。如：
He told me something about his past.
tell sb to do sth 意为“告诉某人去做某事”。如：
David told his son to do the homework.
2. speak 意为“说话、讲话”，后面主要接语言。如：
He can speak English and a little Chinese.
speak to 意为“和.....讲话、谈话”。如：
Can I speak to Mr Zhang?
speak of 意为“提到、说起”。如：
The book speaks of my hometown.
3. talk 意为“谈话、讲话”，如果只有一方对另一方说话时，一般用 talk to；如果双方或多方交谈，多用 with。如：
Please talk to him right now. 请立即同他谈话。
He is talking with his friend. 他在和朋友交谈。
talk about 意为“谈论......”。如：
They are talking about the movie. 他们在谈论那部电影。
have a talk with 意为“与......交谈”。如：
Can I have a talk with you? 我可以和你交谈吗？
4. say 意为“说”。如：
Can you say it in English once more? 你能用英语再说一遍吗？
say to 意为“对......说”。如：
He said to his students that they would have a test.
It is said that... 意为“据说”。如：
It is said that he could stay under the water for a long time.