This means that to describe a person who pushes wagons the compound would change for example from wagon boy to push wagon, pusher wagon and finally to wagon pusher during acquisition.
compounding is an important device for children to expand their vocabularies, and several factors play a role such as productivity, transparency and simplicity (Clark, 1993), with the relation between the frequency of compounds in child-directed (CD) and in their acquisition and use in child-produced (CP) sentences in need of further investigation (Berman, 2011).