this page is about the Spear. Spear has the distinction (along with staff, knife, and the rock) of being a weapon that all cultures have used for hunting as well as warfare. Granted there may be a few cultures that that are so behind the technological line that they haven't shattered a rock for the edge and tied it to a stick to make a spear but I haven't seen nor heard of them.
Anyway The spear has many variations that tend to follow an easily recognized pattern - heavy spear, spear, light spear, double headed spear, short spear, dual short spear, dual double ended short spear. What this means is that anything you can do with a staff, you can do with a spear. The addition is prescision. With prescision staff techniques which are so week as to be laughed at become crippling strikes when used with the spear.
The training that the spear develops is centered on the arms, eye hand coordination, and defense. The spear promotes light footwork as the lightest touch from the sharpened edge can split you open like a ripe fruit. The targets tend to be the joints, tendons, and "anything that shows a pulse" (cross legs here). So blocking the spear really speeds up the reaction time. The blade, being short and far away, builds the eyesight and focus. and the shaft builds the arms. While the power still comes from the waist and legs, the strikes are controlled by the arms. All those little movements that cut things require arm strength and strong wrists. The arm has to be trained as a unit from the middle back to the fingers. Training just the wrist does help if the wrist is your weakest part but if the whole arm is trained this way then it will actually create weak points that will make your spear techniques suck. It won't be obvious to most people but if you train to fight with a spear then it will be so obvious that you will wonder why you thought it was a good idea.
The spear can range from (as far as I know) twelve feet long, to two feet for the dual short spears. The heavy spear would have been the standard bearer's post and the short spear would have been a stick with a knife on the end. Just for comparison the hunting spears would have been more delicate. For small animals you wouldn't need that much and to hunt large animals you would want it to break so while you ran away from say, a pissed off bear, it would blead and be unable to remove the shaft. If it was a dear you could smack it around by the shaft still in your hands.
You could also train to use the spear from horseback or even from a car ( passenger window ) if you really wanted to carry the analogy too far.
A spear form should contain techniques that strike all ranges, mounted enemies, and for retreival of the weapon.
Have fun and don't put your eye out kid.