During the two-word stage children use their limited vocabulary to refer to a large number of unrelated objects.
Overextension: overextending the meaning of a word on the basis of similarities of shape, sound, or size.
EX: use ball to refer to an apple, an egg, a grape and a ball.
This is followed by a gradual process of narrowing down.
Antonymous relations are acquired late (After the age of 5)
The distinction between more/less, before/after seems to be later acquisition.