Deaf Infants Say ‘Goo-Goo’ in Sign Language, Study Shows : Language: Findings indicate babies’ manual and vocal babblings are inherent in the growing brain.

The sounds of “goo-goo” and “dada” that young children make when they begin babbling at about 7 months of age are also made by deaf infants in what scientists say is sign language, according to Canadian researchers.

This “manual babbling” is not simply the random formation of signs, but instead reflects the strict linguistic rules associated with vocal babbling, the researchers report today in the journal Science. The new results indicate that manual and vocal babblings are inherent to the growing brain as it learns the structure of language.

The findings provide strong support for the arguments of linguists such as Noam Chomsky of the Massachusetts Institute of Technology that the human brain has specific biological programming that gives humans the innate capacity for language, said linguist Lila Gleitmanof the University of Pennsylvania.

“What you’re seeing here is that language . . . behaves the same way no matter how it isrealized,” she said. “So, in my favorite old phrase, ‘Deny it to the mouth and it will dart out through the fingers.’ ”

Simply put, the new results “tell us that language is distinct from speech,” said psychologist Laura Ann Pettito of McGill University in Montreal. “Speech is only one of the signals that the human body has available to it.”

Pettito and Paula F. Marentette of McGill studied five infants, who were videotaped at ages 10, 12 and 14 months. Two were deaf infants of deaf parents who were acquiring American Sign Language as a first language. The other three were hearing children with no exposure to sign language.

Pettito and Marentette analyzed the hand motions of the five children in exactly the same manner. They found that the hand motions of the deaf children met all criteria for babbling as much as 71% of the time, while those of the hearing children met the same criteria no more than 15% of the time.

In addition to using the signs and motions characteristic of American Sign Language, the deaf children also passed through the same stages that are observed in vocal babbling. At the age of 10 months, the babbling was restricted primarily to syllables and those syllables were repeated frequently.

Beginning at about 12 months, the deaf children produced so-called jargon babbling--meaningless babbling sequences that “maintained the rhythm and duration of rudimentary American Sign Language sentences,” Pettito said. Finally, the first meaningful words produced by the children incorporated the signs that they had used most frequently in babbling, a known characteristic of vocal babbling.

Another important characteristic of vocal babbling includes the use of syllables, clusters of consonants and vowels, often repeatedly. Also important is the fact that babbling passes through identifiable stages of increasing complexity.

In studies of vocal babbling, researchers typically transcribe all sounds produced over a specific period of time and analyze all sounds that are not words to see if they have any systematic organization. If such organization is found, the researcher determines whether the organization has phonetic and syllabic features common to spoken languages.

“If you find a similarity in the vocal and manual development, you can’t say it’s due to the same motor mechanisms because we know they are different,” Pettito said. “So the similarity is driven by something else” inherent in the brain.

In effect, she said, the brain is “hard-wired” like a computer to develop language in a certain way. That is, it is apparently the way in which connections are made between individual cells in the brain that determines the way language ability is acquired. Unfortunately, she added, “we have no way to test that now.”