BBC NEWS | Technology | Robot unravels mystery of walking

"Babies use a lot of their brains to train local circuits but once they are trained they are fairly autonomous."Only when it comes to more difficult things - such as a change of terrain - that's when the brain steps in and says 'now we are moving from ice to sand and I have to change something'.

“This is a good model because you are easing the load of control - if your brain had to think all the time about walking, it’s doubtful you could have a conversation at the same time.”

This approach to robotics is not new (as far as I know it was pioneered by Brooks at MIT, and sure enough, the academic paper references Brooks). Neither is an equivalent view of language. But I like the simple way it is expressed in this quote. First, it is important to keep in mind that this is only an analogical rather than directly descriptive view of language. Much confusion has sprung up from taking Krashen’s notion of grammar as an ‘affective filter’ on language production too literally. However, there are many phenomena in language where such local effects are in evidence. They should not be confused with the notion of linguistic modularity, though. Many of these local phenomena overlap with other local phenomena and from certain perspectives disappear altogether.

One class of these are my favorite local grammars. We don’t need to know that much about English to be able to find ‘definitions’ in a large corpus. Another type are activities associated with parsing. In fact (recalling Krashen again), we could rephrase the above into “one could not process language (or the rules of language) and have a conversation at the same time.” Parsing a sentence is a local phenomenon handled away from regular speech (this does not necessarily require that there be a neural locus for any of this). First and second language learning bring forth another class of local language effects, as does text editing or writing poetry. None of these activities require the activation of a complex central neural process. They can happen locally (again, I have no idea what locally would really mean, it is the analogy that I’m trying to use to elucidate something puzzling).