A complete list of all steps currently defined by ROUNDALAB along with their timing and phase can be found here
The following description of the rhythm is from the Harold and Meredith Sears website http://haroldsears.com/dance/figures/tango.html
Tango
4 beats/measure; 26-34 meas/min
Tango originated in Argentina during the eighteenth and nineteenth centuries, and of course this was the Argentine Tango, a Latin rhythm. Argentine musicians brought the tango to Paris in 1909, rumors of the tango reached England in 1910, and the dance quickly became popular in England and in America prior to World War I. Interestingly, it was not Argentine dancers who popularized the tango in the USA. It was Vernon and Irene Castle during the 1910s, Rudolph Valentino in the ’20s, Arthur Murray and Xavier Cugat in the ’30s, and even Julio Iglesias in the ’90s.
Originally, the Argentine Tango was an earthy dance and many were offended. By the 1930s the tango had undergone more changes than any other ballroom dance in order to refine it enough to be able to bring it into “proper” ballrooms. Walking steps were introduced to make it progress around the room. The music was speeded up, made more aggressive, more march-like. Movements became sharper, more stylized, more snappy or jerky. A lot of the flirtation, temptation, and passion was taken out. Chris & Terri Cantrell have suggested that, “The American Tango is like the beginning of a love affair, when you are both very romantic and on your best behavior. The Argentine Tango is the next stage when you are in the heat of passion and all kinds of emotions consume you. The International Tango is like the end of the marriage, when you are staying together for the sake of the children.”
Eddie Palmquist simply said that in Argentine Tango the lady is saying “yes”; in American Tango she is playfully saying “maybe”; and in International Tango it is a definite “no.”
International, or English, Tango is so changed from its origins that it is considered a Smooth or Standard rhythm, rather than Latin. It is a flat dance with no regular rise and fall and normally down into the knees. It is appropriate to lower a little into a hinge, lunge, or other picture figure, and then you will rise a little coming out of that picture, but this “rise and fall” is slight and occasional - most of the time, tango is flat.
Tango is also characterized by a staccato emphasis on each beat, alternating rests and actions, and a lengthened stride. Take the step sharply and hold it, step and hold. One teacher asked us to imagine two cars approaching a red light. One driver hurries up to the light, stops abruptly, and waits. The second driver takes his foot off the gas and slows. The light turns green as he approaches, whereupon he gently accelerates again. The first car is tango. The second is foxtrot, slowly arriving and continuing on without ever coming to a stop.
International Tango emphasizes the use of quick steps and uses slow counts for contrast (American Tango uses more slow steps and uses the quicks for contrast).
In addition to making the steps sharp, there is no foot swivel. Even during a “swivel,” (e.g., outside swivel - see below) put the foot where it should be, and then turn the body on that foot. Don’t rotate the foot on the floor. The foot should hit the floor and stick. Tango is jerky but in a dramatic and even haughty way. Don’t smile. Don’t even look at your partner except maybe down your nose during a Right Lunge or at the end of a Spanish Drag.
The hold is closer than in waltz and the man perhaps more in control. Wayne and Barbara Blackford describe a technique for getting yourselves into good tango closed position. First assume your usual closed or waltz position. Then swivel a little left face, soften the knees, fit your four knees together like puzzle pieces, and shift the toes of your right foot to the instep of the left. Your steps will be a little pigeon-toed. A tap, for instance, will be on the inside of the lead big toe.
He places his right arm farther around the lady, and he brings his left hand closer, bending the left elbow a bit more. She places her left hand farther around, under his right shoulder blade, palm down and fingers and thumb together. She must put herself well into his right arm – she is farther to his right and has stronger left sway than in other smooth rhythms. You are very close with her right hip bone tucked firmly into the pocket of his right hip. Glue yourselves together and dance as one, your trail feet stepping well between those of your partner, but let left sway separate your toplines. Keep your torsos up and proud. Again, don’t look at her. Tango is maybe the best rhythm in which to practice your lead and follow.
Since you have rotated a little left face, you will walk with a little right-side lead. Step forward on the outside of the left foot and roll to the inside edge, on the inside of the right foot and roll to the outside edge. The steps are a little bit crab-wise and curved a little to the left. The right-side lead does this. Walk heel to toe, skimming the floor. Wayne says to walk “sticky.” Place each foot and then stop; step and stop. Judy Moore says to step as though you are negotiating lily pads - step, be still, step, be still . . . Brent Moore says that there is much “stillness” in tango. There is no flow, no flight, no swiveling on the balls of the feet.
In the other smooth rhythms, the body is always in motion, in smooth and graceful arcs. In tango, the body doesn’t move past the foot. The foot and the body move together. When the foot stops the body stops.
Round dancing mixes the three tango styles, so in this list especially, you will find some American and perhaps some Argentine figures, in addition to the International figures.