>>>The technique places emphasis on the forward sideslipping, the stem turn and the stem swing.<<<
Melf, nolo is right, in the german laguage 'schwung'=swing and simply means a turn with slipping.
A stem turn involves steering all the way around the turn with the edge 'biting' as it were. It is a slow turn, essentially a narrow snowplow turn ,snowplow as opposed to 'gliding' wedge,with the tails apart all the way around the turn. Why it is called a stem turn is that, unlike the snowplow inititation where both tails are pushed out equally and at the same time, from a traverse, the downhill ski edge is held and the uphill skitail is 'stemmed' by lifting or brushing.
The stem swing on the other hand is a faster turn and is the inititation via stem turn and the finish via parallel turn. In the beginning stem swing, aka Stem Christie, the skis are allowed to go parallel at or near when the skis enter the fall line. The advanced stem swing is what you see many skiers do now who think the are skiing parallel turns.
The initiation is a quick one-two weight shift at the initiation with the rest a parallel swing, often ending in a carve with the new skis. This stem is often a tail displacement of only a couple of inches and it's a great way to ski when you are tired and you haven't mastered the latest horizontal shift of the CM
I remember that the term 'christie' was used for sliding turns until the Austrians, I think it was Prof. Kruckenhauser, modernized it to a more discriptive term, swing.
Both Christie and Swing were used to describe a sliding turn and the term Turn was used to describe steered turns. It gradually just went to Turns.