Speak and talk mean the same thing: express ideas and thoughts by words. They can be used interchangeably, but not always.
Speak means to give a speech, to talk to a public assembly formally.
Talk means to converse, to communicate with someone informally.
You can use prepositions to, with, about after both verbs.
I don't usually speak well.
She doesn't talk like I do.
speak to somebody
I need to speak to the principal.
talk to somebody
I want you to talk to me!
speak about something
The chairman is speaking about their plans.
talk about something
What are you talking about?
speak to somebody about something
He wants to speak to the class about the book.
talk to somebody about something
I wanted to talk to my friend about the problem.
Remember the following phrases and proverbs with speak:
speak a language (speak English, German, etc.)
speak up = speak louder
Sasha is speaking! (on the phone)
speak fluently, easy
speak the truth
speak for oneself = to speak about one’s own opinion/feeling
speak to the subject = speak about the topic
the facts speak for themselves = the fact speaks for itself
Actions speak louder than words.
First think, then speak.
Remember the following phrases and proverbs with talk:
talk back = answer rudely, reply with disrespect
talk sense, nonsense
talk to you later = farewell
talk something over – to discuss at some length
talk somebody into something/doing something = to persuade smb. to do smth.
talk somebody out of something/doing something
Great talkers are little doers.
Talk of the devil and he is sure to appear.
We can use either speak or talk in the following expressions, depending on whether the setting is formal or informal:
talk one-on-one or speak one-on-one
talk privately or speak privately
talk face-to-face or speak face-to-face