I don't believe much in such direct machine-mind interface "added" to adults and that would not be ethical to mess with babies.

We already have interfaces with the extern world: sensors and effectors. If they are not connected at birth and appropriately trained, they will not be effective later. A blind person at birth that recovers later cannot make sense of the new deluge of information.

What we do currently makes a lot of sense, we create extensions of our existing senses and effectors (displays, cars...). We have a better understanding of this interfaces to the world than about our brain internal working.

This idea of machine-mind interface is implicitely based on the (probably false) assumption of an existing brain "API". As I said about existing human effector and sensor, this API exists as a potentiality but fully develop only if we use these sensors and effectors.

About thought formalized thru language, things are even more complicated. How could we hook directly to something we don't know anything substantial about.

A good (but not recent) book about language and learning is "theorie du langage et de l'apprentissage" which is the report of meetings between Chomsky, Piaget, Papert and many other luminaries. I don't know if there is a English edition though.

-- stefp -- check out Nemo