(1) The maturation of the brain and hemispheric lateralization may affect an individual's ability to acquire a second language. The left hemisphere typically controls language functions, though evidence is conflicting. (2) Researchers disagree on when lateralization is completed, ranging from age 2 to puberty. Earlier completion may enable children to more easily acquire a second language. (3) Factors beyond neurological development, like motivation, social context, and age of acquisition, also influence second language success. Some research challenges the idea that adults cannot achieve native-like proficiency.

1. Age and acquisition
Neurological Considerations
Ana Raquel Ribeiro de Freitas

2. Does the maturation of the brain at some stage
show the failure of language acquisition ability?
How might
neurological
development
affect
Second language
success?

3. As the brain
matures, certain
functions are
assigned to either
the left or right
hemisphere.
Some scholars have singled out the lateralization of
the brain as the key for answering such question.

4.  So language functions appear to be
controlled mainly in the left
hemisphere, though there is good deal of
conflicting evidence.
 Hemispherectomies- capable to produce
language
 Stroke or accident in the left side-
laguage impairment

5. Neurobiological considerations
 Hemispheric lateralization – when
lateralization takes place
Lenneberg
(1967)
Lateralization
begins at
around 2 and
is completed
around puberty
Geschwind
(1970)
Lateralization
Is completed
much earlier
Krashen
(1973)
Lateralization
Is completed at
5 years old
Scovel
(1984)
Lateralization
emerges at birth
is evident at 5
is completed at
around puberty

6.  Scovel also proposed that there is a relationship
between lateralization and second language
acquisition.
 He suggested that the plasticity of the brain prior to
puberty enables children to acquire not only their
first language but also a second language- and
that is possibly what makes difficult for na adult to
acquire fluent control of second language or at
least to acquire it without the what Guiora call
“authentic”(nativelike) pronunciation.

7.  In 1988, Scovel also suggested the possibility
of a critical period not only for first language
but also for second language acquisition.
 One the most complelling arguments for a
accent related critical period was the
evidence of sociobiological critical period in
various species
Sociobiological critical period mammals
birds
human beings?

8. (1) To form an identity with their own community as
they anticipate roles of parenting and leadership
(2) To attract mates of “their own kind” in
an instinctive drive to maintain their own
specie.
Walsh and Diller(1981) : concluded that different aspects of a
second language are learned optimally at different ages.
Lower order process such as pronunciation are depending on
early maturing and less adaptative macroneural circuits- which
makes foreign accents more difficult to overcome after
childhood.
High- order language functions such as semantic relation are
more dependent on late maturing neural circuits.
That sociobiological evidence persuades us to conclude that native
accents and therefore foreign accentes after puberty maybe genetic
leftover which, in our widespread human pratice of mating across
dialectal linguistic, and racial barrier, is no longuer necessary for
the preservations of human species.

9.  Right-Hemispheric Participation
There is a significant right
hemispheric participation particularly
in early stages of language learning
Obler (1981)
Genesee (1982)
Scovel (1982)
supported
did not support
“There may be greater right
hemisphere involvement in
language process in bilinguals
who acquire their second
language late relative to their first
language and bilinguals who learn
it in informal contexts
Conflicting evidence

10. Sorenson (1967)
“The Language acquisition seen in adult language learners in
the largely monolingual American middle class speech
communities may have been inappropriately taken to be
universal…” (Hill, 1970)
So how some adults have been know to acquire na
authentic accent in a second language after the age of
puberty?
Hill
Response to Scovel study – antropological
research on non-western societies where adultss
can in the normal course of their lifes acquire
second language perfectly.
Tukanos tribes of south Africa- at least
two dozens languages are spoken
among this tribes- people marry outside
their group- adolecents can speaks 02 or
3 languages they are sposed to. In
adulthood they may acquire more
languages.

11.  Today researchers are continuing to
quest for answers to child-adult
differences, by looking beyond
neurological factors
 Fledge and Morris for example cites
motivation, affective variables , social
factors that can also influence that kind
of acquisition.

12. Thanks
References
Douglas Brown, H. (2007) Principles of language learning and teaching. White Plains, NY:
Longman.
Chapter 3: Age & acquisition