The sound of two hands babbling

by David Sugarman

Everyone is familiar with babies babbling. At about seven months, no matter what the parents' language is, babies the world over take their first steps into language by producing these speech-like sounds. The human mind seems to be built for language at a very early age. Babies hear their parents speaking, and try out sounds as their vocal muscles and their brains' language centres develop. But what do babies of deaf parents do?

Scientists in Canada and the US compared babies exposed only to sign language with those of speaking parents. Using cameras and an optical tracking device, the researchers recorded all of the babies' hand activities as they played. What they found was that the babies exposed to sign language displayed a type of slow-movement hand activity not seen in the babies exposed to speech. This slower hand activity corresponded to the rhythmic patterns of adult sign-syllables and occurred close in front of the body where most signing takes place. This "hand babbling" was very different from the hand activity of the speech-exposed babies, which took place much farther away from the babies' bodies.

The scientists concluded this could only happen if babies are able to recognize and use the rhythmic patterns underlying all human languages, whether spoken or signed.

Surprises do come in very small packages.