Language Learning vs. Language Acquisition

What do you think? Does one "learn" a language much like any other cognitive endeavor? Or is it "acquired" due to some innate language-specific biological mechanism?

There's quite a bit of controversy on this issue, on whether some universal grammar (UG) is responsible for language acquisition, deriving from an innate process specific for language. For those taking the UG approach, acquisition results from the UG module while "learning" is due to normal learning processes. Not all agree. For example, consider Christiansen and Chater's working paper, "Language as Shaped by the Brain". Here's the abstract:

It is widely assumed that human learning and the structure of human languages are intimately related. This relationship is frequently suggested to be rooted in a language-specific biological endowment, which encodes universal, but arbitrary, principles of language structure (a universal grammar or UG). How might such a UG have evolved? We argue that UG could not have arisen either by biological adaptation or non-adaptationist genetic processes. The resulting puzzle concerning the origin of UG we call the logical problem of language evolution. Because the processes of language change are much more rapid than processes of genetic change, language constitutes a “moving target” both over time and across different human populations, and hence cannot provide a stable environment to which UG genes could have adapted. We conclude that a biologically determined UG is not evolutionarily viable. Instead, the original motivation for UG--the mesh between learners and languages--arises because language has been shaped to fit the human brain, rather than vice versa. Following Darwin, we view language itself as a complex and interdependent “organism,” which evolves under selectional pressures from human learning and processing mechanisms. That is, languages are themselves undergoing severe selectional pressure from each generation of language users and learners. This suggests that apparently arbitrary aspects of linguistic structure may result from general learning and processing biases, independent of language. We illustrate how this framework can integrate evidence from different literatures and methodologies to explain core linguistic phenomena, including binding constraints, word order universals, and diachronic language change.

In brief, learning a language is like learning any other skill.

More recently, the National Institutes of Health released news on a six-year study on brain development in healthy children. The study followed the brain development of about 500 children, ages 6-18, each child being tracked over a four-year period. One finding (accompanied by caveats) undermines the notion of language being innate:

Children appear to approach adult levels of performance on many basic cognitive and motor skills by age 11 or 12, according to a new study coordinated by the National Institutes of Health (NIH). ...

Regardless of income or sex, children appeared to improve rapidly on many tasks between ages 6 and 10, with much less dramatic cognitive growth in adolescence. This result fits with previous research suggesting that in adolescence, there is a shift toward integrating what one knows rather than learning new basic skills.

In other words, there is a "critical period" for learning general cognitive tasks that corresponds to the critical period for "acquiring" a language, usually considered to be up until the age of 12, after which individuals will not develop a complete command of a language. In Error Feedback: Theory, I mentioned the 10-year rule, which states that becoming an expert requires at least 10 years of intense practice, a period of time similar to achieving nativelike fluency in a second langauge.

If language learning has a similar critical period time frame as other endeavors and takes similar amounts of time to become an "expert," then it would seem to be governed by general cognitive learning processes rather than by a language-specific learning process.

These findings do not contradict Krashen's assertion of the need for massive comprehensible input for learning a language. After all, the crucial element for achieving mastery of any activity is, as Anderson and Schunn (pdf) state,

For competences to be displayed over a lifetime, time on task is by far and away the most significant factor.

As teachers, then, one of our primary tasks is to motivate students to spend the necessary time in learning a language (see Error Feedback: Motivation, The Inverse Power of Praise, and Engagement and Flow).