The short answer is: nobody knows. There has been much speculation about the origin, mostly having to do with the corruption of "Moorish" or "Moresque" to "Morris." Moresque dances commemorated the fall of Moorish Spain in the 14th century. There are also groups of "Morisken Tanzers" in the Bavaria region of Germany. However, there is little evidence of Morris and Moresque being connected other than the coincidence of name.
Another theory is that a group of Oxford musicology students were trundling along a road through the English Cotswolds when their Morris Minor automobile broke down. One of them started playing accordion, and the other students found that by hitting the engine rhythmically with sticks they were able to keep the car going and made it to their destination.
That depends on what you mean. WE, the Foggy Bottom Morris Men, are from America (in particular, our nation's capital)...well, except for those of us who were not originally from here but are currently living here.
The DANCES are English in origin; some date back to before Shakespeare's time, and others were written as recently as last week.
You could get into a long philosophical discussion about whether we have Americanised it and how much, but I think we'd rather just do another dance and have another beer. If you do try to start that conversation, then it will also be your turn to buy a round.
Nothing in particular, other than visual or sound effects to enhance the dance. Of course, the usual spiel is that the noise and activity "awaken" Spring. This appears to be a relatively modern (from the early 20th century) interpretation promulgated by some of the first generation of Morris revivalists. Apparently, they thought they detected "pagan" origins in the dance and romanticised about ancient peoples, standing stones, fertility rituals and the like. Whether early pagans actually even used handkerchiefs is open to debate. Again, if you wish to start that debate, the next round is on you.
The movements do represent the dancing styles found in different villages. A practiced eye can detect which style of Morris dance is being performed by the type of stepping, the way hankies are waved, and the rhythm of the sticks. A jaundiced liver helps, too.
Yes, many! Most major cities in the US have at least one team, and there are many in more rural areas as well, especially on the west and east coasts, and particularly in New England. Here is a link to a morris wiki which lists many (if not all) of the Morris teams in America, England, and other parts of the world.
There are many teams in Washington D.C. and the surrounding areas. Among some of the regional teams we frequently tour with are (in alphabetical order):
Each member has his own reasons, of course, but basically, we do it because it's fun. Don't believe it? Come to one of our practices!