Baby talk. Is it idle infant banter or part of an innate process
of language development?
That’s what UBC psychologist Prof. Janet Werker and graduate student
Christine Stager are trying to find out.
“We know a lot about language acquisition around age two, but less
about the period between one and two years,” says Werker, who has
spent more than 20 years studying language acquisition in infants.
“We’re interested in understanding how babies move from being sensitive
to the sounds of language to mapping those sounds onto words.”
Until Werker and Stager published the results of their most recent
three-year study in the scientific journal Nature, researchers
didn’t know what information babies stored as they learned new words.
“We now realize they’re storing less than we thought,” says Stager.
During their first year, babies listen carefully to the sounds
of the language spoken around them. By 10 to 12 months they can
distinguish between consonants and vowels spoken in their native
language from the same syllables spoken in another language.
At around 14 months a change takes place.
Werker and Stager discovered that at that point babies begin to
ignore some of their previous information so they can focus on learning
words.
“They’re efficient little problem-solvers,” says Werker. “They
focus on what’s needed and drop what’s not. It’s an automatically
assured process in learning language.”
To make this discovery, the researchers observed some 64 babies’
reactions to word-object pairing using a new technique co-developed
with UBC graduate student Valerie Lloyd and researchers at the University
of Texas.
Brightly-coloured moving objects were shown on a monitor in front
of the baby. As objects appeared, they were paired with the syllables
“bih” and “dih”, announced through a speaker below the monitor.
When first exposed to the word-object pairings, babies showed their
attention by concentrating on the screen. After the same pairings
had been seen repeatedly, their attention wandered to other objects
and sounds in the room.
Werker and Stager watched to see if babies noticed a difference
when objects or syllables were switched.
They didn’t.
In a previous study Werker had found babies at this stage were
capable of distinguishing between the sounds “bih” and “dih,” yet
in this study they acted as if they were the same syllable.
“All their attention is focused on matching the sound with the
object,” says Stager. “They’re already working at full capacity.
To get the job done, some detail gets ignored.”
At ages three to four, when word learning is no longer difficult,
infants return to distinguishing between subtle phonetic differences
such as “bih” and “dih.”
Understanding these stages in language development may be useful
in working with children with delayed language or learning disabilities,
says Werker.
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