The critical period hypothesis (CPH) claims that once humans hit puberty, then start learning a second language, the process becomes more difficult. It says that the younger people learn a language, the better they master it in across skills areas. At first, it was a hypothesis that was only applied to first language acquisition. It studied the problems and difficulties in children who were unsuccessful in learning their first language for some reason. Later on, it was applied to second language acquisition. It strongly supported that within humans happens a biological change that makes it harder for them to develop language skills after roughly the age of 11. This research will discuss the claims of the critical period hypothesis that support the possibility of achieving an ultimate phonological attainment, such as, accent-free speech, of learners of English as a second language, and the reasons behind this ultimate attainment.
As a researcher, it interests me how people have different accents. It is interesting that although as English language speakers with different ways of uttering the phonemes of English, we are still able to understand one another; This supports my belief that as English second language learners, our goal should not be the achievement of native-like levels. In her book English with Accent, Lippi-Green supports that the main goal of learning a second language should be to understand and to be understood transactionally in all areas of skills. An attainment that is near-native should not be the destination of ESL students (2011) . A number of studies are being initiated more often to either support or refute the claims of CPH. It is important to demonstrate both sides’ claims, and present the information of both sides’ selected studies before portraying how strong the evidence of the CPH is when it comes to mastering an accent-free speech.
2. Examples of studies that refute the Critical Period Hypothesis (CPH):
The Definition of the Critical Period Hypothesis (CPH):
Many scholars and linguists, such as Wilder Penfield and Lamar Robert, defined the Critical Period Hypothesis as the time from childhood to adolescence (1959). In that period of time every human being, if started to learn a second language within, he or she will achieve a native competence in his or her second language. The reason is that when children learn their second language, their brains acquire them like they acquire their first language. For example, it is believed that older English language learners rarely to seldom utter an accent-free speech and that is because they passed the critical period. Note here that the CPH does not state that people cannot learn a second language as many people may interpret the hypothesis, but it simply says that second language learners, after the age of puberty, cannot achieve a native-like level. However, many scholars who belong to different schools of thought believe that the critical period hypothesis is false. Some of them believe that it can only be applied to first language acquisition, as acquiring a first language is a natural process that is affected by a biological change, unlike learning a second language that is about explicit knowledge and cannot be affected by age or a biological change. Others believed that the Language Acquisition Device in our brains (LAD), as Chomsky called, does not limit itself to a certain period and that is Language is a human need and we can learn it at any age.
Refuting the claims of the Critical Period Hypothesis:
1. Study One:
In a study done by Lydia White and Fred Genesee (1996), How native is near-native? The issue of ultimate attainment in adult second language acquisition, they claim that the results of studies done to support the claims of the CPH are not accurate due to the samples those studies observed. To White and Genesee, studying non native speakers who did not reach a proficiency level in their second language attainment will support the claims of the hypothesis. They also believe it is better to study those who are proficient and near native speaker, and then compare their results to native speakers to observe whether there is a significant difference or not. The researchers White and Genesee selected 89 people for their first sample that consisted of second language learners of English with average age of 29. Then the sample was divided into two groups; 51 non native speakers were born in Canada, and 38 non native speakers were immigrants to Canada. Then again the same sample was divided into another two groups; 45 people considered near-natives and 44 people were considered non natives. The second sample consisted of 19 native speakers of English with average age of 28 years old. Interviews were conducted intensively in English. A Thematic Apperception Test (TAT) was chosen to be performed during the interview. The test administrator shows a series of pictures to the test takers and ask them to tell a story about each picture. It is used to analyse the personalities, as it is believed that individuals will tell stories according to their own interest, concerns and the way they feel (Vane, 1981). Those interviews were recorded and then showed to two judges who were chosen to be native speakers of English. They were told to rate the subjects in a scale of 18 point range in all skill areas, each skill individually. 18 as native and 0 as non native. They were not told which of the subjects were immigrants, natives or born Canadian. All non natives who scored 17 or 18 were considered near-natives. Exceptions of native speakers and near natives who scored 16, had this scoring due to phonological errors. After that, the test takers were given two different tasks to complete; a grammatical judgement test, and a question formation test. The results of this study when analysed found that there is no significant difference in the scores of natives and non natives. Regardless to the background of the test takers, it was shown that some near natives scored higher than natives. White and Genesee believe that no critical period determines whether people can achieve a near native level in skill areas (White, & Genesee, 1996).
2. Study Two:
In her 2011 study, Vocabulary Size and Depth of Word Knowledge in Adult-onset Second Language Acquisition, Hellman considered previous papers in various linguistics areas such as neurolinguistics studies and behavioural studies, and realised that age plays a role in all aspects of language attainment in second language learning. She also claimed that most of the research of the past four decades concluded that L2 learners do not achieve the level of native speakers; and if any learner reached a native-like level, it would be in one or two skills. It is out of the norm for a late learner to master a native-like level in all skills (Hellman, 2011). the goal of this study was to carefully observe the size (quantity of words known) and the depth (quality of words known) of the lexical capacity in adult-onset second language learners who extensively are exposed to English, in order to decide whether they achieved ”a native-like lexical attainment” in their L2, and what factors were involved in their attainment. Hellman selected three main samples to study. Each sample consisted of a number of participants. The first sample consisted of 33 adult-onset of English; Native speakers of Hungarian who moved to the US between the ages 14 to 24. Hungarian was purposefully chosen for its zero similarity to any Latin Language. Sample 2 consisted of 30 native speakers of English who did not acquire any other language beside English (Monolingual). The last sample selected were the 30 native speakers of English who are bilingual, and are proficient in the second language they acquired. The study consisted of three methods of testing lexical attainment. Hellman used the Peabody Picture Vocabulary Test (PPVT). It is an aural based test with time duration: 15 minutes, Self-Rated Vocabulary Test (SRVT) – written based – with time duration: 15 minutes, and Word Association Test (WAT) – written based – with time duration: 15 minutes, along with interviewing the participants with a questionnaire distributed and an oral interview in time duration: 90 minutes. The results of the study showed that with the intrinsic and extrinsic motives and learning new vocabulary, people can reach a native like level in their lexical attainment, with consideration of the background and the time spend in the targeted language environment, and that is age does not play a role in achieving an ultimate native-like lexical attainment (Hellman 2011).
Reflection on the studies mentioned above:
Observing the data of the previous researches and their findings, one can say that there are some openings to argue and prove the power of the age playing a role in phonological attainment in second language learners of English. In the first study mentioned by White and Genesee, they mention that the reason the group of the some subjects scored less than natives is because they had some phonological errors. Another observed aspect in their study that can be argued is the instruments they focused on; The Grammar Judgement (GJ) test and the Question Formation (QF) test. Both instruments do not measure the phonological level of the subjects. Therefore, it is hard to claim that in the area of Phonetics, those subjects achieved their proficiency with no age factor involvement. In the second study mentioned by Hellman. She acknowledges the fact that achieving a native-like level in phonological skills is hard for second language learners of English who start acquiring it in later stages of life. She states in her 2011 study Vocabulary size and depth of word knowledge in adult-onset second language acquisition ‘’Studies have revealed that native-like performance in the area of Phonology is rare with few adult second language learners being able to produce accent-free speech under experimental conditions’’ (p. 163). However, she believes that an L2 learner might achieve a native like level in one or two areas, but not all. Her study only focused on lexical skill but it also recognized the almost impossibility of producing accent-free speech (phonological-wise) for non-natives even if the exposure to the targeted language was of young age.
3. Claims to support the Critical Period Hypothesis (CPH):
- The differences between acquiring a first language (FLA) and a second language (SLA):
Being familiar with the fact that both FLA and SLA share some similar aspects and different ones, we observe in the similarities and differences how age plays a role in acquiring a language whether our first or second language. According to Brown’s book Principles of Language Learning and Teaching, when acquiring a first language or a second, Universal Grammar crucially affects the learning process. Another similar point between FLA and SLA is that learners acquire both languages through 4 stages; (1) Random error stage, (2) Internalisation of language governed rules, (3) Self-correction of language mistakes, and (4) Improvement and usage monitoring of language, and the completion of language system. Learners may vary in the time they spend during each stage but they cannot skip one to the next. A significant similarity between FLA and SLA is the influence of age in achieving a proficient level in the targeted language. In the beginning stages of learning a language – FLA or SLA – learners tend to produce less than they understand. Their competence of the targeted language is richer than what they can perform. They go through a stage where they tend to be silent and observe the uttered speech around them to build their underlying knowledge of language. Brown mentions that according to Chomsky, learners of language – SLA or FLA – can be proficient in a context while not in some other. That proficiency or mastery of language can be in some areas and not others.
Furthermore, Brown mentions some differences in acquiring a first language and a second language. Concerned only with those that are age-related, the first difference is that in second language acquisition an explicit knowledge of the language is required, and the underlying knowledge of the first language would help building the second language knowledge. Unlike first language which is completely governed by Universal Grammar (UG). In contrast, L2 adult learners do not completely rely on UG in their learning process. Thus, they are less likely to be aware of the phonological units that do not exist in their native languages. Therefore, their chances to reach a native-like level – specially in producing an accent-free speech – is more likely reduced. Another difference is when children learn their first language they go through the stages of babbling, cooing and gooing, and they spend years before they formulate a complete meaningful sentence (Yule, 2007), whereas in learning a second language, adult learners are taught how to form a sentence, therefore, in much shorter time, adult learners of L2 are able to produce a complete sentence. Eliminating all exception cases of disabilities and isolation, everyone learns a first language and must reach a native level in their L1. Especially that they have the opportunity to interact with natives of their surroundings and their caregivers. However, not everyone can learn a second language, and not everyone can reach a near-native or a native level in their L2. Also, learners of L2 do not often have the chance to interact with native speakers of their L2 (Brown, 2007).
2. Accents and Other Considerations that supports the CHP:
Previously, we agreed that it is almost to be a consensus among linguists that it is not the norm of ESL learners to achieve a native-like level in their phonological skills, and those who were able to produce a merely accent-free speech are the exceptional cases. Brown in his 2007 book Principles of Language Learning and Teaching elaborates and mentions several studies that supported this claim. First he mentions several studies conducted by Gerald Neufeld in 1977 through 2001. Neufeld wanted to know to what extent learners of L2 can utter a native like speech. In his early studies 1977-79, he recorded 20 native speakers of English uttering and reading words and sentences in Japanese and Chinese. Then these tapes were heard by native speakers of Japanese and Chinese. The results showed that 11 of them were native-like Japanese and 9 of them were native-like Chinese. Then he did the same thing in 2001, but with English speaking French. He concluded that ‘’older students have neither lost their sensitivity to subtle differences in sounds, rhythm, and pitch nor the ability to reproduce these sounds and contours’’ (Brown, 2007, p. 63). However, the results of Neufled were not considered reliable due to the information the judges were provided with prior to their judgement about the subjects of the studies. Next is the study of Bongaerts (1995) that was done on a number of Dutch who learned English in later stages of their lives, and native speakers of English. Both samples were asked to record themselves reading passages in English and uttering individual words. The results then were judged by native speakers of English. However, some native speakers of English were judged as non-natives! I think this confirms that accent perception differs from ear to ear, and there is no such thing as a standard accent for native speakers.
There are some considerations to hold in mind that are aspects within ourselves that change before and after puberty that can affect our second language acquisition. For example, the human cognition changes very fast during our childhood. However, once we hit puberty our cognitive does not develop as fast. It becomes slower and more gradual in the process of developing. Therefore, according to Ausubel (1964), it is useless to teach children the grammar of languages and the rules that govern that language. They will not benefit from them as they acquire languages naturally and implicitly. Unlike adults who will more likely succeed if grammar is explained to them explicitly. Another aspect that changes within us is what Guiora et al called Language Ego in The study of personality variables in second language learning . As humans we grow to like the languages we speak. Our attitudes towards languages and races and the people they speak them does not appear when we are kids. Therefore, learning a language does not affect our preferences. While as we grow up, we formulate ideas and are affected by the environments and culture, where we can develop an attitude towards a language or the people they speak it, which in return makes it difficult to develop language skills in certain languages (1972). Lastly, acquiring a language in young children differs from how adults acquire it. Children learn both FLA and SLA the same way. Their brains treat both languages as one. They develop one meaning system for both languages. Therefore, it is easier for them to mix up both. As for adults, it is not the same process. Therefore, code switching is more difficult to process in adults.
4. Conclusion of the Research: Concluded Aspects and Suggested Further Studies:
As shown in the previous sections, it is obvious that a native level of phonological competence or performance is hard to achieve by ESL late learners. However, that does not eliminate the fact that there are some cases that achieved a native-like level, nor does it eliminate that in aspects like lexical skills, an ESL learner can surpass natives in the ultimate achieving (Hellman 2011). It is important to note that this ultimate achievement – especially in phonology – is not what learners of ESL should seek. We all know people who have strong accents but are still understood and can understand native speakers of English. However the studies that refuted the claims of CPH, as presented, have their flaws; Like the reliability of raters and judging, or flaws in the methods conducted.
Moreover, the fact that some cases of isolated children, who could not develop a first language after they were discovered, supports the claim that language is biologically linked. For example, the famous case of Genie the wild child who was discovered at the age of 14, abused and neglected. Although after she was discovered she was taught language extensively to communicate, still she could not perform correct english grammar sentences. Instead of Saying ‘’I am hungry’’, she would say ‘’Genie hungry’’. Another evidence is that in cases of brain damage and injury, adults are more likely to suffer of severe linguistic damage, unlike children’s brains that can adapt to the damage and change accordingly to avoid any linguistic impairment. Thus, though rare, physicians can perform a hemispherectomy on children but cannot perform it on adults.
Finally, further studies to investigate both the importance of accents and speech variation production should be conducted more often. It is fascinating how the brain and language work. It is important to initiate such studies with the right tools of measurement and procedures. Such as Early Speech Perception Test (ESPT), Auditory-Verbal Ages and Stages of Development, or Test of Auditory Comprehension of Language (TACL). Such tests can be developed too to serve the purposes of phonological assessment and speech production. Such studies and tests too can be used with adults as well as children. It is also suggested to interview ESL learners more often to know their phonological weaknesses and strength. Interviews will also provide information about the strategies ESL learners apply when they are not being understood by, or cannot understand native speaker of English. Knowing about those strategies will give us insight on the needs of ESL learners too.
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