Spears are weapons consisting of long poles, usually made of wood with a sharpened end of any material, which varied upon the civilisations sophistication, technology and resources. Those of Ancient Egypt, for example, were made of copper, whereas those of China at the same time were made of bronze or iron.
Spears are used for both hunting and warfare. They were the staple weapon of the common soldier as they were easy to make, and were the most effective for anti cavalry. Lightened versions could also be thrown, but early versions were simly too heavy.
The Elves probably made their own and used it for hunting while still in eastern middle-earth before the Great Journey. After returning to Middle-earth in pursuit of Morgoth, the use of the spear changed from just hunting to use in war.
When men awoke in the First Age, they probably made their own and used it for hunting or perhaps warfare. Later, learning from the elves, they probably perfected it and passed it down to future generations up to Númenor and onward.
- Spear at the Wikipedia