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Is there really a critical period for accent acquisition?

Faculty op-ed

By Stephen Krashen and Nooshan Ashtari Published on

Until recently, it was assumed that there was a neurologically based “critical period” for the full acquisition of a second language or dialect of our first language: It was thought that a native speaker of English growing up in Los Angeles cannot expect to acquire a fully convincing version of French, or speak English like a New Yorker or Southerner, unless exposed to that style or language as a child, before puberty, regardless of the amount of exposure to that style of speaking after puberty. The most popular version of the neurological barrier has been long disproven (Krashen, 1973), yet the concept of a critical period is still accepted. We present here a different point of view: speech style is a marker of “club membership,” of belonging to a certain group, a group based on features such as education, ethnic background, social class, the place you grew up in, or even personality. In fact, marking “club membership” appears to be the main function of accent and dialect.

Our hypothesis is that we can and do acquire languages and dialects other than the version we acquired as children, and this ability is available throughout life. There is no critical period for language acquisition. We are, however, often very reluctant to use what we have acquired: An “output filter” stops us from using a style of speaking that is used by members of a group that we feel we do not fully belong to. When we are imitating, joking, or telling a story, we can speak using dialects of a language that are much closer to native speaker accents than the accents we would use in “normal” conversation. In normal conversation, however, we do not use these accents. In an interview, master polyglot Peter Ustinov said “If I’m being myself, I have an accent.”

Club Membership and Comprehension

We often assign club membership to people before we hear them speak, based on their appearance. This can affect perception of speech. In one study (Rubin, 1992), subjects heard a speech sample spoken by a native speaker of English. Subjects were shown either a picture of a “Caucasian-looking” or an “Asian-looking” subject and were told that the person in the picture was the speaker. Subjects who saw the picture of the speaker with “Asian” features were more likely to say they heard an accent when none was there. Ashtari (2014) reported a similar phenomenon. Eighty-percent of advanced ESL students reported that native speakers of English said that they did not understand them when they spoke English even though their grammar was reasonably accurate. Even the appearance of a light accent combined with looking slightly different or “foreign” led to the assumption that their English language competence was low.


The club membership hypothesis affects our production AND our perception. We are inhibited from using a style of speaking that we have acquired but that is not associated with a club we belong to, even if we have acquired it very well, and we sometimes think we hear an accent when one is not there, influenced by the speakers’ appearance and apparent club membership (Krashen and Ashtari, 2021). Accents and identities are also significantly intertwined. Having a foreign accent can be both connected to how we feel welcome/accepted by the native speakers of our second language, as well as maintaining our own original accent to show how we identify with our native language/culture and our desire to retain our primary identity. The "foreignness" in our speech in this regard can be part of our identity that we do not necessarily want to give up/diminish by becoming speakers of other languages as witnessed within the different immigrant populations worldwide (Krashen & Ashtari, forthcoming).

Can Other Versions be Taught?

The Limits of Instruction Can we consciously “learn” second languages and different styles of our first language, versions that we have not acquired naturally? Many people think so and think that it can be done by “study”: Hammond (1990) interviewed adult native speakers of Spanish living in Miami who had studied ESL for at least two years. Fifty-one percent agreed that “hard-working and intelligent people can always succeed in eliminating a foreign accent” (p.145).

But there is little evidence supporting the hard work hypothesis. Hard work is, of course, study, and a popular version is taking accent improvement classes. The research, however, shows that this kind of hard work is of limited value: Saito and Plonsky (2019), after an analysis of 77 studies, concluded that “… pronunciation teaching is most effective when it targets specific pronunciation features and when gains are measured using controlled tasks (word and sentence reading)” (p. 40), similar to the conditions that need to be present for the use of consciously learned rules of grammar. (Krashen (2013) reported on six descriptions of commercial accent improvement programs. Only one of the six referred to evidence supporting the program developers’ claims that their program was effective, but the only citation was an unpublished Master’s thesis.)

Peter Ustinov, a skilled actor who had an astonishing ability to imitate a variety of accents, said that his ability to convincingly imitate accents did not come from study, but from imagining the character; In other words he used what he had naturally acquired from listening (Peter Ustinov on Mimicry and Accents, as cited in the references: YouTube).

Emeritus Professor of Education Stephen Krashen PhD is the author of more than 525 articles and books in the fields of bilingual education, neurolinguistics, second language acquisition and literacy.

Nooshan Ashtari PhD has spent the last two decades teaching languages, graduate/undergraduate courses and conducting research in various countries around the world. Her main research interests include technology and education, heritage language development, gender in language use, as well as reading in second language acquisition among others.



Ashtari, N. (2014). Non-native speech and feedback: The relationship between non-native speakers’ production and native speakers’ reaction. The International Journal of Foreign Language Teaching, 9(2), 9-17.

Hammond, R. (1990). The affective filter and pronunciation proficiency – attitudes and variables in second language acquisition. In Arena, L. (Ed). Language Proficiency: Defining, Teaching, and Testing. NY: Plenum Press.

Krashen, S. (1973). Lateralization, language learning, and the critical period. Language Learning 23: 63-74. PDF

Krashen, S. 2013. The effect of direct instruction on pronunciation: Only evident when conditions for monitor use are met? GiST: Education and Learning Research Journal 7: 271-275. PDF

Krashen, S. and Ashtari, N. (2021). Is accent in the mind of the listener? Language Magazine 21,2:27. https://www.languagemagazine.com/2021/10/18/is-accent-in-the-mind-of-the- listener?

One Sunny Day. (2020, Nov 25). Peter Ustinov on Mimicry and Accents [Video]. YouTube

Rubin, D. (1992). Non language factors affecting undergraduates’ judgments of nonnative English-speaking teaching assistants. Research in Higher Education 33:511-31.

Saito, K., & Plonsky, L. (2019). Effects of second language pronunciation teaching revisited: A proposed measurement framework and meta-analysis. Language Learning, 69(3), 652–708. https://doi.org/10.1111/lang.12345

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