I had a student today who asked me the difference between speak, talk, say, and tell. Leaning back and thinking for a second, I realized that I was unsure. I mean, I knew to a certain extent but not nearly enough to explain it. That was enough for me to go out, research the words, and make this post–so here goes!
Speak is used to illustrate how people use words. For example, “I speak English.” I use English words. Another example is “Please speak louder.” In this case, you would want to “use” your words more loudly. It can also be used as a command, such as “Speak up!”
Say is used to introduce quotations, or something someone has said at some point. For example, “I said, ‘I don’t want to go to the store.'” If you were writing an essay, you might say “The author says that literature is necessary to the advancement of man.” Although there is no direct quotation in that sentence, it is referring to something that the author said at one point.
Talk refers to communication, or people who are communicating. For example, “I talked to the vet today.” It shows that I was communicating with the vet. Another example is “I need to talk to you.”
Tell is used for giving information or teaching. “Please tell me what to do.” You would give me information about what to do. “Tell me what’s wrong.” You would provide me with information about what is wrong.
Speak and talk are almost entirely interchangeable. Speak is a more formal version, like when you want to talk to a superior: “May I speak to the manager?” Talk is more common when you’re referring to equals.