This document summarizes a study that tested the critical period hypothesis for second language acquisition. The study compared the English proficiency of 46 Korean and Chinese speakers who arrived in the United States at different ages, from 3 to 39 years old. Results showed that those who arrived before puberty performed better and had higher proficiency levels than those who arrived after puberty. Performance was correlated with age of arrival up to puberty, providing support for the idea that there is a critical period for second language acquisition.

1. Communicative Competence:
Theory and Classroom Practice.
Texts and Contexts in Second
Language Learning. The Addison-
Wesley Second Language
Professional Library Series.
By. Savignon, Sandra J.

2. HYPOTHESIS
Language could be acquired only within a critical period,
extending from early infancy until puberty. In its basic form,
the critical period hypothesis need only have
consequences for first language acquisition. Nevertheless,
it is essential to our understanding of the nature of the
hypothesized critical period to determine whether or not it
extends as well to second language acquisition. If so, it
should be the case that young children are better second
language learners than adults and should consequently
reach higher levels of final proficiency in the second
language.

3. QUALITATIVE TYPE OF RESEARCH
 This prediction was tested by comparing the English
proficiency attained by 46 native Korean or Chinese
speakers.
 The participants had arrived in the United States
between the ages of 3 and 39.
 They had lived in the United States between 3 and 26
years by the time of testing.

4. PROCEDURE
 These subjects were tested on a wide variety of
structures of English grammar, using a grammatically
judgment task.
 Both correlational and t-test analyses demonstrated a
clear and strong advantage for earlier arrivals over the
later arrivals.
 Test performance was linearly related to age of arrival
up to puberty; after puberty, performance was low but
highly variable and unrelated to age of arrival.

5. FINAL RESULT
The results support the conclusion that a critical
period for language acquisition extends its effects
to second language acquisition.

6. WHY DOES THE AUTHOR CHOSE THIS
KIND OF INVESTIGATION?
It is proven and throughly studied that the critical period is
fundamental towards a second language acquisition.
I believe the author chose to investigate this because; first
of all is a subject that, in my opinión, is interesing to study.
Furthermore, the author wanted to stablish his own opinión
according to the critical period.
Knowing and proving any hypothesis you want, can easily
help you to instruct a second language.

7. REFERENCE
 This research was supported in part by NIH Grant NS
16878 to E. Nand T Supalla, and by NIH Training Grant
HD07205to the University of Illinois.
 http://www.sciencedirect.com/science/article/pii/00100
28589900030ewport