New research shows that infants learning more than
one language do more lip-reading than infants
learning a single language and by the end of their
first year, infants have narrowed their ability to
perceive different languages if they have not had
exposure to them.
In the study, bilingual and monolingual infants were
observed watching a video of a woman speaking in
Spanish or Catalan; the infants were learning one or
both of these languages. Lewkowicz and his
collaborators found that bilingual infants focused
their attention on the mouth at an earlier age and
for a longer period of time than monolingual infants.
This suggests that bilingual infants pick up on
salient audiovisual speech cues more than their
monolingual peers to help them distinguish between
the two languages they are learning simultaneously,
he said.
“These results provide new insights into the
underlying mechanisms of people’s ability to acquire
more than one language at the same time early in
life,” said Lewkowicz, a professor in the Department
of Communication Sciences and Disorders in
Northeastern’s Bouvé College of Health Sciences.
Lewkowicz and his co-authors Ferran Pons and Laura
Bosch, both at the University of Barcelona and the
Institute for Brain, Cognition, and Behavior in
Spain, report these findings in a forthcoming paper
in the journal Psychological Science. Lewkowicz said
the findings have important implications for
understanding how infants acquire speech and
language and shed light on how bilingual infants,
despite their neural and behavioral immaturity,
manage to learn two different languages as easily as
monolingual infants learn one language.
The findings, he said, could also play a role in
treating and diagnosing children with communicative
and learning disorders like autism.
He noted that children with autism are typically
diagnosed between 18 and 24 months and tend to look
at faces less often than typical children, a factor
that significantly reduces their opportunities for
experiencing audiovisual speech that Lewkowicz’s
previous research has shown to be important for
young babies.
What this means in the context of his research is
that identifying infants with particular patterns of
selective attention to speech could help diagnose
communication and learning disorders earlier than is
currently possible.
In this new study, Lewkowicz and his collaborators
used eye-tracking technology to measure precisely
how much time infants attended to the eyes and mouth—the
two critical areas that we focus on during social
communication—of a person who could be seen and
heard speaking. The infants all lived in Spain and
were learning Spanish and/or Catalan.
The researchers found that, regardless of what
language the person spoke, 4-month-old monolingual
babies looked longer at the eyes than the mouth but
that 4-month-old bilingual babies looked equally as
long at the eyes and mouth. Similarly, whereas
12-month-old monolingual babies looked equally at
the eyes and mouth in response to native speech and
more at the mouth in response to non-native speech,
12-month-old bilingual babies looked longer at the
mouth regardless of language and, critically, longer
than monolingual infants in both cases.
These findings build upon Lewkowicz’s groundbreaking
research published in 2012, which showed that babies
learn to talk not only by listening to sounds but
also by lip-reading. Findings showed that as babies
start to babble, at around six months of age, they
begin to shift their attention to the mouth of the
person speaking. In essence, they begin to lip-read,
having discovered how much salient speech
information they can learn from watching a person’s
mouth.
In the previous study, two experiments were
conducted with different age groups of monolingual,
English-learning infants between 4 and 12 months of
age. In these experiments, the infants watched
videos of women speaking either English or Spanish.
In addition to finding that babies begin to shift
their attention to a talker’s mouth after 6 months
of age, this study showed that 12-month-olds
attended to the mouth longer when the person spoke
Spanish than when she spoke English, presumably
because what had now become an unfamiliar language
was more difficult to understand.
These findings led the researchers to pursue this
latest study. Upon learning that combined auditory
and visual speech information is very important for
speech and language acquisition in infancy, they
wondered whether babies growing up in a bilingual
environment take even greater advantage of these
combined auditory and visual cues and, thus, whether
they lip-read even more.
“That’s precisely what we found,” Lewkowicz said,
adding that “These findings shed new light on
bilingualism, which happens to be of great interest
to researchers studying the effects of early
experience as well as policymakers concerned with
integrating non-English speaking children into the
classroom.”
Lewkowicz noted that his team’s research offers
insight into what kinds of information to expose
children to in order to help them acquire two
languages more effectively. Babies, he explained, go
through an intense period of learning in the first
year and during this time they acquire expertise in
their native language. Paradoxically, while
native-language expertise emerges, babies’ ability
to perceive other languages declines, a process
known as perceptual narrowing, he said.
“By the end of their first year, infants have
narrowed their ability to perceive different
languages if they have not had exposure to them,” he
explained. “This process happens very rapidly and
earlier than we thought, though children still
retain a great deal of plasticity throughout
childhood. But certainly, if you don’t get exposed
to another language during childhood, you’ll have
difficulty learning it later on.
“The flip side of this is that exposure to multiple
languages in infancy prevents narrowing, and it is
now clear that one way in which bilingual infants
manage to accomplish their task is by taking maximum
advantage of both audible and visible speech
whenever they interact with their social partners.”
See also
Bilingual Effects in the Brain (31/07/2012)
Toronto researchers find first physical evidence
bilingualism delays onset of Alzheimer's symptoms
(20/10/2011)
For more information
Northeastern University
Study: Bilingual infants lip-read more than
monolingual infants
Universitat de Barcelona - Institut de Recerca en
Cervell, Cognició i Conducta (IR3C) - Facultat de
Psicologia
MDN |