Quoting Burun:

My native language is Finnish...

In Finlandif you say to a stranger: Can I talk with you?
It means like: You in deep trouble Sir...
And again to a stanger: Can I talk with you?
You are in trouble Sir...

But for a friend: "can I talk to you?"
I have some imortant information
Can I talk with you?
I have an idea, but i can wait

My wild quess is this:
"Seninle konuşmak istiyorum" may mean both "Sir, you are in deep trouble" or I have some importatnt information to my good friend and
"Sizinle konuşmak istiyorum" may mean: "Sir, you are in very deep trouble" or "Hey you tourists, you are in trouble" or "My friends, i have to talk with you" ^^

I may be wrong and correct me if I am wrong