In fact, the idea of universal grammar contradicts evidence showing that children learn language through social interaction and gain practice using sentence constructions that have been created by linguistic communities over time. In some cases, we have good data on exactly how such learning happens.
For example, relative clauses are quite common in the world’s languages and often derive from a meshing of separate sentences. Thus, we might say, “My brother … He lives over in Arkansas … He likes to play piano.” Because of various cognitive-processing mechanisms — with names such as schematization, habituation, decontextualization and automatization — these phrases evolve over long periods into a more complex construction: “My brother, who lives over in Arkansas, likes to play the piano.” Or they might turn sentences such as “I pulled the door, and it shut” gradually into “I pulled the door shut.”
What is more, we seem to have a species-specific ability to decode others’ communicative intentions — what a speaker intends to say. For example, I could say, “She gave/bequeathed/sent/loaned/sold the library some books” but not “She donated the library some books.”
Recent research has shown that there are several mechanisms that lead children to constrain these types of inappropriate analogies. For example, children do not make analogies that make no sense. So they would never be tempted to say “She ate the library some books.” In addition, if children hear quite often “She donated some books to the library,” then this usage preempts the temptation to say “She donated the library some books.”
Such constraining mechanisms vastly cut down the possible analogies a child could make to those that align the communicative intentions of the person he or she is trying to understand. We all use this kind of intention reading when we understand “Can you open the door for me?” as a request for help rather than an inquiry into door-opening abilities.
Chomsky allowed for this kind of “pragmatics” — how we use language in context — in his general theory of how language worked. Given how ambiguous language is, he had to. But he appeared to treat the role of pragmatics as peripheral to the main job of grammar. In a way, the contributions from usage-based approaches have shifted the debate in the other direction to how much pragmatics can do for language before speakers need to turn to the rules of syntax.
Usage-based theories are far from offering a complete account of how language works. Meaningful generalizations that children make from hearing spoken sentences and phrases are not the whole story of how children construct sentences either — there are generalizations that make sense but are not grammatical (for example, “He disappeared the rabbit”).
Out of all the possible meaningful yet ungrammatical generalizations children could make, they appear to make very few. The reason seems to be they are sensitive to the fact that the language community to which they belong conforms to a norm and communicates an idea in just “this way.” They strike a delicate balance, though, as the language of children is both creative (“I goed to the shops”) and conformative to grammatical norms (“I went to the shops”). There is much work to be done by usage-based theorists to explain how these forces interact in childhood in a way that exactly explains the path of language development.
