KSS
Which is the correct form?
Speak to .....
or
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"
does, IMHO.
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.