The article was developed to deal with the common debate that common formulation of the critical period hypothesis that younger is always better in L2A. The article claims that according to critical period hypothesis, first language acquisition needs to take place prior to the completion of cerebral lateralization, around puberty age.
The authors make one anticipation of the aforesaid hypothesis, stating that second language acquisition is likely to be more rapid, successful, and qualitatively same as the first language if and only if it happens prior to the puberty age.
This clearly entails that language acquisition after puberty will vary from, i.e. slower than, not as successful as, the first language acquisition before puberty. For the methodology part, the hypothesis was applied to and tested on 51 English-speaking participants grouped in five age categories throughout a period of one year.
All subjects were made to learn Dutch as their second language by adopting it at workplace or school, with very little or no formal education on the language. The authors effectively compared the results with advanced or high level L2 Dutch speakers as well as native Dutch speaking participants.
The findings of this study did not fully support the CPH. Participants aging between 12 and 15 were fastest in acquiring the second language, while those between 3 and 5 were the slowest and scored poorly in all the tests than the older group members.