Verbal, Material and Somatic, also known as movement. These are the three building blocks of most forms of magic. Some spellcasters have learned to specialize in one of these forms; Verbal spellcasters are also known as bards or spellsingers, depending on the world. Material spellcasters are best represented as the Dwarven Runecasters. The Somatic specialization, often overlooked, is known as Spelldancing.
The form of Spelldancing is a relatively new one, and as such it is still feeling out its strengths and limitations. It was initially founded by a mage who lost his voice during a summoning accident. While drifting for a while, he took in a performance at the local theater. Midway through the show, the movements of the dancers and his current dilemma seemed to coalesce themselves in his mind. The potential of this idea struck him like a pile of iron bricks. still in the middle of the performance, he lept to his feet, attempted to holler "I’ve found it!" which came out as a loud wheeze, and proceeded to run out of the theater at full tilt.
It was years before he managed to advance his theories to the point where he could cast even the simplest of spells. It was a historic moment when, deep in the bowels of a library, the mute mage danced an odd little dance, something between a jig and a square dance, and a small orb of light popped into existence.
In the years since, the mage has attracted numerous students, either bards attempting to expand their repertoire, nobles seeking to stand out at ballroom dances or any of a multitude of others. The discipline has gained much popularity in the nobility, for it provides "a dignified way for the true gentleman to work magic". Through them (and specifically their wallets) the school has advanced at a rapid pace. While still not as developed as the more traditional spellcasting forms, it is growing at a much quicker pace. Given a century or two, it may actually catch up.
Any existing spell that relies purely on motion (somatic components) can easily be modified to be cast through Spelldancing. Other spells can also be modified, though with varying levels of success. Sometimes the effect changes in a purely cosmetic way, and others it can become either much more powerful or simply not have an effect at all. Many spells simply cannot be cast through Spelldancing, regardless of how much time is spent working on it.
There are some changes from standard magic that seem to apply to all Spelldancing spells:
-Most spells affecting light seem to be slightly more powerful when cast through Spelldancing. A light spell will be brighter, and magical darkness will be harder to dispell.
-To date, all spells that create fire have been observed to create less fire, but the fire itself is much hotter. As such, it usually is a blue flame.
-Spells that alter the way the caster moves, such as flight spells, are easier to cast with Spelldancing than with traditional spellcasting, to a point where a Spelldancer could cast a water walking spell while a more experienced traditional spellcaster couldn’t.
-Spells that create physical objects simply don’t work with Spelldancing. You could dance until you’re blue in the face, you won’t make a sword pop into being.
-Spells that buff up people other than the Spelldancer are greatly reduced in effect, weaker spells of the sort having no effect at all. The same goes for curses and the like. They have normal effect if the Spelldancer casts them on themselves, however.
Remember, Spelldancing is a new form, and has many other quirks that have yet to be discovered. This is by no means a comprehensive list! Also due to the youth of the school, it has yet to develop any spells unique to itself. It is certainly possible, but to date most efforts have been focused on understanding the form better. There is no doubt that Spelldancers will begin creating new spells in the future, it simply hasn’t happened yet.