Greek term of address "lo"?

So, I went out to the plateia and asked some of the older people - difficult for me and for them because my Greek is so poor. But anyway, they told me that it's spelled λω , and is specific to Lakonia. Most younger people think it's slang, but it's actually a very old word used as a particle of respect when a younger person addresses someone older. It's used in the villages and in Sparti, but probably nowhere else in Greece. No wonder a Greek from elsewhere wouldn't recognize it. Greece is a small country on the map, but isn't small in any other way.