Language acquisition is a dynamic interaction

The caregivers actually used simpler language the closer the boy got to grasping a word. At the point they sensed he was on the cusp of getting it, all three primary caregivers – Roy, his wife and their nanny – simplified their language to guide him to the word, then gently brought him into more complex language once he passed the hump.

“For each of the primary caregivers we found the same trend,” Roy said. “We’re getting longer sentences when he doesn’t know the word, and then they start getting shorter, and they’re pretty much at their shortest as he starts to get the word…. Was I consciously doing that? I can’t imagine anyone consciously doing that.”

Roy says it’s evidence of a “continuous feedback loop” that shows caregivers modifying language at a level never reported or suspected before. It’s not just that his son was learning from his linguistic environment, the environment was learning from him, he told the TED audience.

The finding has changed his thinking about causality.

“I now think looking for linear cause effects —where the environment causes certain effects in my child — is a bad formulation,” he says. “Because … as soon as you have feedback loops, it’s a chicken and egg kind of problem to say what was the original cause of something. What you’re actually doing is studying a dynamical system.”

http://www.wired.com/epicenter/2011/03/deb-roy-at-ted/