It makes you sound like you have a good education but no one can tell quite where you are from. You hear it in old Hollywood films from the 1930s and 1940s. It is the accent of Cary Grant, Katherine Hepburn, William F Buckley and (at least in some films) God.
There is no town in the world where people grow up speaking English that way. Instead you get the accent in one of three ways:
1. Learn the accent on purpose (actors used to do that).
2. Grow up or live on both sides of the Atlantic (but that can lead to even stranger accents, like those of Loyd Grossman and Madonna).
3. Pick it up at a top boarding school in America before the 1960s.
Abagond has some tips to help you cultivate a Transatlantic accent. Link -via Cynical-C
Super interesting!!
http://www.youtube.com/watch?v=ylJ5PP3W9zQ
On the up-side, I'm easy to understand. People from other countries enjoy talking with me, because they have an easier time understanding what I said than they do with most Americans. Occasionally I'm even asked if I've ever been on radio! On the down-side, I get a lot of teasing from people who feel insecure and have heavy regional accents (I remember wasting 5 minutes' class time trying to understand what I'd thought was a question from a student. It turned out he was saying "Say 'Deptford,'" [a nearby town], and it sounded like a half-mumbled "Sedeffert?" with the "question" sound at the end. He [and the kids who put him up to this] just wanted to hear me say "Deptford" so they could laugh at my pronunciation. After they'd had their laugh, I informed them they'd wasted 5 minutes, and any further questions should be submitted in writing and signed. Stupid questions would be answered with a detention.) I think most of the students at that school thought I was Canadian, British or Osama bin Laden. Sigh... (No, I don't look like bin Laden.)