Like regional dialects, the hand signals on different trading floors vary. We enlisted Al Manafo, a trader on the floor of the

American Stock Exchange

and a 21-year veteran of the business, to demonstrate the basics of what has become something of a waning art.

With the addition of more TV screens tracking the movements of stocks, clerks and brokers are often no longer able to see one another and thus, can't signal. "As often as not, the line of sight is not available," says Steven Lesser, a senior vice president and member liaison at the exchange. Also, over time, the nature of the business has changed. More orders get to the crowd on the floor electronically, he says, via wireless or other devices. Of the 864 members of the Amex, he estimates a couple of hundred of the old-timers who've been there more than 10 or 15 years still know and use the pantomimes.

Will they eventually disappear altogether? That's difficult to know, says Lesser. "That will be answered only when we see how the exchange evolves." For now, watch the finger play with the video links below. (You may need to adjust your sound level to hear.)

Hand Signal Video Clips

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Click on picture to see letters.

Click on picture to see numbers.

Click on picture to see a transaction.