critical period

Sarah Ennis

Lennenberg’s hypothesis in 1967 proposed a critical period for language learning. He inferred that infants must be exposed to their a language within a window of time, beginning early in infancy until puberty when the lateralization of the brain is complete, in order to properly learn language. At the time Lennenberg proposed this theory little evidence was available to support this claim. Over the years however, researchers have collected plenty of convincing evidence that support the notion of a critical period of language acquisition.

I think some of the most compelling evidence for a critical period besides the Nicaraguan Sign Language discussed in class is study by Johnson and Newport (1989), which examined the grammatical abilities of Chinese and Korean immigrants. The immigrants in this study ranged from 3 to 39 years of age. All of the immigrants had been living in the U.S. between 3 and 26 years. Each individual was tested on his or her grammatical mastery of the English language. The results indicated that immigrants who came before age 7 knew as much grammar as a native-born adult. Those who came between the ages of 8 and 10 knew it slightly less well; those who came 11 to 15 knew it somewhat less well; and only a few of those who came after the age of 15 acquired any grammar skill at all (Johnson & Newport, 1989). This remarkable study demonstrates that universally a critical period likely exists in order to learn language. It could be said that this study only demonstrates the likelihood of properly learning a second language and cannot be compared to learning an initial first language. However, because those individuals who migrated to the U.S. before the age of 7 scored comparable to native speaking adults this explanation is likely untrue.

It is easy to imagine how it would affect a child who is not exposed to any language at an early age if in fact a critical period does exist. There have been few instances when this phenomenon has unfortunately occurred. Like these instances, a child who is not exposed to language during a critical period will struggle with the ability to learn critical abilities like writing or the ability to acquire knowledge in school. The inability to master these two skills would especially impair the success of the child immediately and also later in life. Furthermore, children who do not properly acquire language would be unable to participate in a critical part of development: socialization. They would struggle with how to communicate or form relationships with others.

Language is the foundation for our ability to function, survive, and adapt to our environment. It the tool that gets us to where we want to go. Without it our opportunities to flourish in life and social relationships are greatly impaired. The overwhelming evidence supporting a critical period is important when we consider what can occur if we are unable to learn language.