Originally posted by ling.speed:

What we have in game is a javelin not a spear, which we can add to collection of wrongly named things, like Coal. :reimu5:

I like to imagine that its a particularly flimsy/short one, so it can be used only one handed to stab.

You just described a hunting spear (an "épieu" in French). You also just described a tier-1 weapon for peasant militia and Germanic tribal levees as Hobo said. I'd even expect that the spear in Valheim has an additional special attack with its blunt end.

Spears are no pikes, nor sarissa, but they can be looked like a short hoplitic dorys (2 meters long, the height a character in Valheim). They were meant to be used single-handly, together with a shield, except when receiving charges.