The age factor in L2 and the critical period hypothesis

Compare child and adult language acquistion in a second language ADULTS CHILDREN Who are better in the short term? Who in the long run? Have you hear about “the logical problem of language acquisition”? What does it refer to? If you read the quote by Chomsky, what is the the logical problem? “The gap between available experience and attained competence” forms the logical problem. The question is how can we have such rich, complex and varied capacity that goes beyond what we can derive from experience. “The problem demanding explanation is compounded by other factors: despite variation in backgournd and intelligence, people´s mature linguistic capacity emerges in a fairly uniform fashion, in just a few years, without much apparent effort, conscious thought, r difficulty; and it develops with only a narrow range of the logically possible “errors”” (Lightfoot, 1984: 20) “The question is how children acquire so much more than they experience” p21 “Normal children attain a fairly rich system of linguistic knowledge by five or six years of age and a mature system by puberty; this is impressive when compared with the labourious efforts of squads of adult linguists who educated and trained up to the eyeballs, try with only moderate success to characterize explicitly what people know when they know Dutch, Hopi, or whatever” p21

How can we account for these differences? Is it a matter of learners´ characteristics and learning conditions? Is it a matter of biological constraints (Critical period hypothesis)?

The Critical Period Hypothesis (CPH) The critical period hypothesis states that there is a period during which langugage acquisition is easy and complete and beyond which it is difficult and typically incomplete.

Lenneberg (1967):

Lenneberg (1967): People who lost linguistic capabilities, for example as a result of an accident, were able to regain them totally before puberty (about the age of 12) but were unable to do so afterwards. The neurological basis of language in children and adults is different.

Penfields and Roberts (1959): First ten years of life the brain retains plasticity. After puberty, there is lateralization of the language function in the left hemisphere. Brain is not equipotential like the brain of the rats, which functions holistically. Through lateralization different areas of the brain control different language functions. (Scovel, 1998) Have you hear about “the logical problem of language acquisition”? What does it refer to? If you read the quote by Chomsky, what is the the logical problem? “The gap between available experience and attained competence” forms the logical problem. The question is how can we have such rich, complex and varied capacity that goes beyond what we can derive from experience. “The problem demanding explanation is compounded by other factors: despite variation in backgournd and intelligence, people´s mature linguistic capacity emerges in a fairly uniform fashion, in just a few years, without much apparent effort, conscious thought, r difficulty; and it develops with only a narrow range of the logically possible “errors”” (Lightfoot, 1984: 20) “The question is how children acquire so much more than they experience” p21 “Normal children attain a fairly rich system of linguistic knowledge by five or six years of age and a mature system by puberty; this is impressive when compared with the labourious efforts of squads of adult linguists who educated and trained up to the eyeballs, try with only moderate success to characterize explicitly what people know when they know Dutch, Hopi, or whatever” p21

Lateralization Cerebral cortex (gray matter) Motor cortex Sensory cortex Broca´s area Wernicke´s area

Take your left hand and cup it over your ear so that the palm of your hand is clapped over your ear hole. Middle finger (Broca´s area). Index finger (Wernicke´s area).

Broca´s area Wernicke´s area Role Aphasia Speech production/Processing of the structure of sentences/Unclear role Comprehension / sounds of words and aspects of meanings (nouns) /looking up words (sending them to Broca´s area to assemble or parse them) Aphasia Slow speech /Hesitant/ungrammatical/ also processing problem e.g. the car is pushed by the truck Fluent but lack of communicative purpose (cannot process conversational feedback)/neologisms/ difficulty naming objects)

Evidence for the CPH in L1. Aphasia (indirect evidence) Evidence for the CPH in L1 Aphasia (indirect evidence) Human cases of language deprivation (Victor, Isabelle, Genie) Study of deaf population

Genie (1970) Initial cognitive development: 15 month level Final cognitive development: 6-8 year-old L1 acquisition: Early development: same stages of child L1 development one-word utterance then two-word utterances longer sentences with negation some prepositions, plurals and possessives Final state (after many years of exposure and training): Negative sentences with “no” at the beginning Minimal definite/indefinite articles “bathroom have big mirror” Usual SVO order Language level of a 2.5-year-old.

The Critical period hypothesis in L2 Newport and Johnson (1989): “Critical period effects in second language learning: The influence of maturational state on the acquisition of English as a second language” Previous studies: Patowski (1980): Differences between pre- and pos- puberty learners of English. Age of arrival only significant predictor of syntactic proficiency. Oyama (1978): Age of arrival, rather than attitudinal variables, predicted language performance.

The Critical period hypothesis in L2 Create a research space (niche/gap in knowledge): How could they contribute to previous studies? Expand on language sample taken from subjects Wider range of ages Authors´ purpose: 1. Examine relationship between age of exposure and and overall measure of English proficiency, as well as the possible differential effects of age of exposure on various aspects of grammatical structure. 2. Examine a wide range of ages of exposure to establish the precise shape of the function relating age to proficiency. In other words, how does age (1st exposure to L2) relate to ultimate level of language proficiency within the CP?

The Critical period hypothesis in L2 Researchers´ questions: Is there an age-related effect on learning the grammar of a second language? If so, what is the nature of this relationship? What is the shape of the function relating age to learning and ultimate performance, and where (if anywhere) does the relationship plateau or decline? Can experiential or attitudinal variables, separately or together explain the effects obtained for age of learning? What areas of the grammar are the most and least problematic for learners of different age groups? Variables Results Conclusions

The Critical period hypothesis in L2 Results and discussion: There seems to be a strong linear relationship between age of exposure to the language and ultimate performance in that language, up to adulthood. Subjects first exposed to English at 3-7 no decline in language ability 8-10 slight decline 11-15 sharper decline 17-39 their ultimate level of proficiency was not related to the age at which they were first exposed to English. Some scored very high and some very low. Great variation (Cf. Bley-Vroman)

The Critical period hypothesis in L2 Results and discussion: We did not find a flat relationship between performance and age of learning throughout childhood, with a sudden drop in performance marking the end of the critical period; instead, performance gradually declined from about age seven on, until adulthood. (p. 110) For adult learners, age does not continue to be a predictor of performance (…) A theoretical account of critical period effects in language learning must therefore consider whether the skills underlying children´s uniformly superior performance are similar to those used by adult learners, or rather whether adult language learning skill is controlled by a different set of variables. (p.111)

The Critical period hypothesis in L2 Results and discussion: There is the nature of the relationship between age of arrival and performance: a ……….. decline in performance up through puberty and a subsequent lack of linearity and great ………….. after puberty. (p.111)

The Critical period hypothesis in L2 Results and discussion: There is the nature of the relationship between age of arrival and performance: a LINEAR decline in performance up through puberty and a subsequent lack of linearity and great VARIABILITY after puberty. (p.111) What accounts for this decline?

The Critical period hypothesis in L2 What accounts for this decline? 2 different explanations: … that there is maturational change in a specific language acquisition device (Chomsky 1981; Lenneberg, 1967) p.112 … an increase in certain cognitive abilities may, paradoxically, make language learning more difficult. p.112