The acquisition of abstract grammatical constructions represents the maturation of a child’s linguistic productivity. This productivity means that a child can take constructions that have already been learned and extend the application of the construction by using different words.
One way to identify if the child has utilized a new construction in a productive way is to look for overgeneralizations in the application of the construction. For instance, things that sound like mistakes in a child’s speech might actually represent the analogical extension of a learned construction into new lexical territory to attempt to communicate something that the child understands, but which is outside of the acquired bank of constructions. Children sometimes use intransitive verbs in a transitive construction. While this overgeneralization of the transitive construction is ungrammatical, it does represent an attempt at productive use of learned lexical concepts in learned constructions. Adults encountering overgeneralizations may be able to determine what the child is attempting to communicate as the actual utterance represents an encoding of a concept with the construction as the foundation of meaning with the intransitive verb as the domain of meaning. “He falled me down” (Bowerman 1982, cited in Tomasello 2003) is an attested case which indicates that the child has not acquired the appropriate transitive verb to describe the situation of being knocked over, even though the child has acquired the transitive construction.
This is a strategy of innovation in conversation, and may have insight for second language acquisition; when a construction for a particular concept is known, but the lexical particulars are unknown, adapting lexical particulars that account for the general concept and using them in a known construction permits the fielding of the ill-formed utterance and enabling the negotiation of meaning to take place.