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The Correlation Between Language Loss and Age

In an increasingly connected world, learning a second language online or at school has come to be encouraged and even expected of many students. With practical benefits ranging from career opportunities to sociocultural ones, taking a lesson on Duolingo doesn’t seem like too much of a hassle. But learning a second language (L2)—and falling out of using your first—can lead to a process known as language attrition, where a speaker’s fluency in their first language (L1) gradually decreases after learning their second (Ahn et al. 2017).

Research work in L1 attrition has received relatively little attention compared to L2 attainment work (Ahn et al. 2017; Schmid 2015). Linguistics Professor Monika S. Schmid, a prominent researcher in the field, mentions that “attriters” may even feel isolated in their struggle due to lack of awareness (Schmid 2015). Additionally, in a comprehensive review of the existing literature, Gallo and colleagues suggested that more attrition-related studies must use brain-imaging techniques to gain a better foundational understanding of the phenomenon (Gallo et al. 2021). This again indicates that our current understanding of the neural basis of language attrition is significantly lacking.

Despite these challenges, fascinating studies on the temporal importance of the onset of language attrition have been conducted over the past several decades. These studies have tried to determine whether the age at which an individual learns their L2 significantly impacts the progression of L1 attrition.

One such study investigated this issue by having 68 Chinese-Korean and Russian-Korean bilingual children aged 11-14 years old complete the HALA task, an experiment designed to test participants on their word retrieval speed and accuracy in both languages. The researchers found no correlation between the age of L2 acquisition and the participant’s L1 word naming accuracy. Instead, Kim and Kim found that the “relative amount of L1/L2 input” was more strongly linked to language attrition in bilinguals (Kim and Kim 2022).

It’s important to accept these results with discretion, though. The participants of Kims’ study were not diverse in terms of their age, as all of the recruited children were 11-14 years old. The study also directly challenges some of the previous research that has been done on relating age to language attrition. One such study conducted by linguistics professor Emanuel Bylund found evidence for a “critical period” in which children tend to forget their first language more easily before the age of 12 (2009). These conflicting results demonstrate that the Kims’ suggestion that the age of L2 acquisition plays an influential role cannot be taken as absolute. The need for further study on this topic is therefore evident.

While the Kims’ study doesn’t answer our questions about whether a critical period for language loss exists, it’s still a step forward in bilingualism research: the results show a clear need to differentiate between one’s age of L2 acquisition and relative exposure to first and second languages. As scholarly interest in L1 attrition continues to grow, acknowledging this difference will prove to be instrumental in understanding the cognitive and psychological processes that underlie both language acquisition and loss.


Works Cited:

  1. Ahn, Sunyoung, et al. “Age Effects in First Language Attrition: Speech Perception by Korean-English Bilinguals.” Language Learning, vol. 67, no. 3, 20 July 2017, pp. 694–733, 10.1111/lang.12252. Accessed 20 Nov. 2019.

  2. Bylund, Emanuel. “Maturational Constraints and First Language Attrition.” Language Learning, vol. 59, no. 3, Sept. 2009, pp. 687–715, 10.1111/j.1467-9922.2009.00521.x.

  3. Gallo, Federico, et al. “First Language Attrition: What It Is, What It Isn’t, and What It Can Be.” Frontiers in Human Neuroscience, vol. 15, 7 Sep. 2021, 10.3389/fnhum.2021.686388. Accessed 24 July 2022.

  4. Gorsky, Emily. “Why Learn a Second Language? The Benefits of Bilingualism.” Berlitz, 21 Jan. 2020,

  5. Kim, Kitaek, and Hyunwoo Kim. “Sequential Bilingual Heritage Children’s L1 Attrition in Lexical Retrieval: Age of Acquisition versus Language Experience.” Bilingualism: Language and Cognition, vol. 25, no. 4, 10 Jan. 2022, pp. 1–11, 10.1017/s1366728921001139. Accessed 16 Mar. 2022.

  6. Schmid, Monika. “What Is Language Attrition?” Language Attrition, 18 Nov. 2015,

  7. StudySmarter. “Critical Period: Definition, Hypothesis, Examples | StudySmarter.”,

  8. University of Hawaiʻi at Mānoa. “HALA Project | University of Hawai’i at Mānoa Department of Linguistics.”, Accessed 27 Jan. 2023.


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