There's a phenomenon that has interested me for a while, and I noticed a extreme example last weekend. When people mean "yes" they sometimes say "no, yeah" or "yeah, no" and when they mean "no" they say "yeah, no" or "no, yeah" or even "no, yeah, no."

On Saturday I was sitting next to someone at a lunch, and I counted four consecutive times when she said "yeah no" in place of "yeah." For example: "Did you like Columbia?" "Yeah no I loved it." (In fact, once I started looking for it, I never heard her say a simple "yeah.") The "no" was almost imperceptible each time, as the meaning was clear, and adding it is a common practice in speech.

Do you have any insight into the practice? Patterns in gender or age or situation or setup?