Speak, talk – differences

When do we use speak and when do we use talk? Here are the differences:

Speak, talk
Speak and talk have similar meanings. They suggest that a person is using his or her voice, or that two or more people are having a discussion.
We say:
speak to somebody (about something)
talk to somebody (about something)
What are you talking about?
Who were you speaking to on the phone?
I was talking to Mark about cricket.
How old were you when you learned to speak?
We say: speak a language
talk a language
talk nonsense
speak nonsense
He speaks four languages.

Stop talking nonsense!
Speak to and talk to are used more often than speak with and talk with. I was talking to Tom yesterday.
Speak to is a little more formal than talk to, and is often used in polite requests. [on the phone] Hello, could I speak to Mr Jones, please?

For more examples of speak/talk, see Stuart’s article Confusing words: speak, talk

Practise ‘speak’ vs. ‘talk’ in an exercise.