Implications in Language Teaching

CRitical period hypothesis & Language learning

As seen in the explanation of Critical Period Hypothesis (CPH), researchers believe that it is impossible, or incredibly difficult, to successfully acquire all aspects of a language beyond the critical period for language learning. In this section, we will not look at whether it is possible to learn a second language later in life; rather, we will focus on how age and other factors can impact learning.

How do we learn a second language?

The "nature of language acquisition" changes depending on a person's stage of development (Lightbown & Spada, 2021, p. 97). According to CPH, during critical periods, innate biological structures contribute to language acquisition (Lightbown & Spada, 2021). Beyond these critical periods, one does not have access to those innate capacities; older learners will have to rely on their general learning abilities and skills in order to learn a second language (L2) (Lightbown & Spada, 2021).

"General" learning abilities refer to students' metalinguistic knowledge, memory strategies, and problem-solving skills (Lightbown & Spada, 2021). Metalinguistic awareness involves knowledge of language itself, and the ability to treat it as an object (Lightbown & Spada, 2021). It allows L2 learners to "solve problems and engage in discussions about [their second] language", and to transfer concepts or structures from their first language that may help with L2 development (Lightbown & Spada, 2021, p. 40). Memory strategies are also an important tool in language acquisition, as learners must first process the language they see or hear in their working memory before acquiring it (Lightbown & Spada, 2021). Since the amount of information you can process at once is limited (Lightbown & Spada, 2021), memory strategies that can help learners organize and process information will allow them to learn more quickly.

These learning strategies develop with age, allowing older learners to use them to their advantage more effectively. As we will see in the next section, this can have effects on a student's rate of learning.

Rate of learning

Older learners begin to acquire a second language much more quickly than younger learners (Lightbown & Spada, 2021). This could be due to older learners using their general learning skills instead of the innate capacities for language acquisition available to them during the critical period. Educators can take advantage of learners' metalinguistic skills or other learning abilities to quickly teach them aspects of the target language. For example, English as a second language teachers can teach their students how to identify and use common prefixes and suffixes (e.g., "ness"). Knowledge of English language structures would allow students to transform adjectives like "happy" or "ugly" into the nouns "happiness" and "ugliness", without having to be explicitly taught each individual form. This would also help learners understand that words ending with "ness" are usually nouns, allowing them to infer the word's meaning (i.e., "happiness" refers to the state of being happy).

When completing language tests, people who began learning a language later in life often perform as well as those who began learning as children; this remains true even if the younger learners received more instructional time overall (Snow & Hoefnagel-Höhle, 1978). Children often learn language "intuitively" by being exposed to a lot of input, and by engaging in communicative instances with others (Lightbown & Spada, 2020, p. 424). However, in situations where learners do not receive enough exposure to the second language, knowing how to effectively use learning strategies is a big advantage (Lightbown & Spada, 2020). Cognitive and literacy skills, along with prior knowledge of one's first language can help adult learners effectively process whatever limited amounts of language they are exposed to in a classroom (Lightbown & Spada, 2020). In contrast, younger learners would not be able to organize and process the language they are exposed to as quickly. This contributes to adult students' faster rate of learning, especially in the beginning stages of second language development (Lightbown & Spada, 2021).

Any other factors?

Age is not the only factor that affects language learning. Aptitude, personality, attitude, motivation, agency, identity, and conditions of learning can all impact how you learn a second language (Lightbown & Spada, 2021). All of these are interconnected, and there is no one deciding factor for successful language learning. For example, age and conditions for learning are often related. Child learners usually have more exposure to the language and opportunities to practice, and feel less pressure to speak (Lightbown & Spada, 2021). In contrast, adult learners who need to use their L2 in their daily lives often need to learn complex features of the second language much more quickly (Lightbown & Spada, 2021). The higher pressure placed on adult learners can also lead to them becoming frustrated if they are unable to fully express themselves in the language (Lightbown & Spada, 2021). These negative emotions can lead to feelings of inadequacy, affecting both motivation and one's capacity to learn (Ormrod et al., 2008).

Although age can change how you learn a second language, it is very difficult for researchers to separate age from other factors affecting language learning. As we have seen above, the conditions in which one learns a second language are often dependent on age, and it can be difficult to ascertain which factor has the biggest impact on language learning.

Is earlier better?

Many educators and policy-makers have adopted the belief that "younger is better" regarding second language instruction (Lightbown & Spada, 2021, p. 101). However, research has shown us that this simply isn't true. Burstall's 1975 study found that some students who had completed early-start programs later ended up being placed in L2 courses in secondary school with beginner students. Furthermore, we have already discussed how older learners can use learning strategies and skills more effectively, allowing them to make the most of any explicit instruction provided in the classroom (Lightbown & Spada, 2021). These examples, along with other research on second language acquisition, have shown us that learning a language earlier does not entail any notable academic benefits (Lightbown & Spada, 2021).

Additionally, intensive exposure to the second language at a young age can be damaging to a child's sense of identity (Lightbown & Spada, 2021). Situations wherein a child is immersed in the L2, and does not have the opportunity to continue developing their mother tongue, may lead to them losing their first language completely (Lightbown & Spada, 2021). Language loss has negative effects on a child's self-esteem, sense of identity, and relationship with family or community members (Lightbown & Spada, 2021). A 'later start' in language learning would give children the opportunity to develop their first language, and successfully maintain it once they begin learning another (Lightbown & Spada, 2021).

Research has proven that an earlier start in language learning does not provide students with any significant educational benefits, and can even negatively impact their identity. However, Critical Period Hypothesis maintains that successful language learning is only possible if you begin learning a language earlier in life, before the critical period ends. This idea is at odds with the research presented above: adult learners are perfectly capable of using their general learning skills to quickly learn a second language, and to attain a proficiency level that rivals that of younger learners. Although CPH provides us with valuable insights into the differences between how adults and children learn a second language, it places too much importance on the age at which one begins learning.