Which is the correct form?
Speak to .....
Speak with ......
Talk to / Talk with
I think if you are speaking/talking with/to people, the preferred choice depends on relative authority, and who's doing most, if not all, of the speaking/talking.
For example, you would speak/talk to an audience, a kid, a crowd, but you would speak/talk with a friend, lover, counselor, priest.
"Speak" has slightly more of an "authoritative" connotation than "talk"
Also, as a noun, you can give a talk to a group, but would more likely have a talk with a person of equal stature.
Also, you can speak/talk to an issue, or a concern, but you would speak/talk with authority, vigor, grace, or humility.
Hope this helps.
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993