This is a small, limited but fascinating study in which a.o. Daniel Yurovsky, assistant professor in psychology at Carnegie Mellon University, looked at how young children are learning a language, in the hope to find models for machine learning.

We’ve known for a long time that adults tend to speak to children more slowly and at a higher pitch. But there is more. The researchers found that they also use more exaggerated enunciation, repetition and simplified language structure. Adults also pepper their communication with questions to gauge the child’s comprehension. As the child’s language fluency increases, the sentence structure, and complexity used by adults increases.

Wait a minute, isn’t that almost like direct instruction? Yurovsky does notice the similarities to the progression a student follows when learning math in school. So, if this is correct, ‘natural learning’ gets a whole new meaning…

As said there are a lot of limitations to this study, and do know that there are a lot of other supported theories on the acquisition of language!

A short description of the study, taken from the press release:

Yurovsky and his team sought to understand exactly how caregivers tune their interactions to match their child’s speech development. The team developed a game where parents helped their children to pick a specific animal from a set of three, a game that toddlers (aged 15 to 23 months) and their parents play routinely in their daily lives. Half of the animals in the matching game were animals that children typically learn before age 2 (e.g. cat, cow), and the other half were animals that are typically learned later (e.g. peacock, leopard).

The researchers asked 41 child-adult pairs to play the game in a naturalistic setting in the laboratory. They measured the differences in how parents talked about animals they thought their children knew as compared to those they thought their children did not know.

“Parents have an incredibly precise knowledge of their child’s language because they have witnessed them grow and learn,” said Yurovsky. “These results show that parents leverage their knowledge of their children’s language development to fine-tune the linguistic information they provide.”

The researchers found that the caregiver used a variety of techniques to convey the ‘unknown’ animal to the child. The most common approach was to use additional descriptors familiar to the child.

Abstract of the study:

Young children learn language at an incredible rate. Although children come prepared with powerful statistical-learning mechanisms, the statistics they encounter are also prepared for them: Children learn from caregivers motivated to communicate with them. How precisely do parents tune their speech to their children’s individual language knowledge? To answer this question, we asked parent–child pairs (N = 41) to play a reference game in which the parents’ goal was to guide their child to select a target animal from a set of three. Parents fine-tuned their referring expressions to their children’s knowledge at the lexical level, producing more informative references for animals they thought their children did not know. Further, parents learned about their children’s knowledge over the course of the game and tuned their referring expressions accordingly. Child-directed speech may thus support children’s learning not because it is uniformly simplified but because it is tuned to individual children’s language development.