The Nature of Learner Error in ELT: Distinguishing Errors from Mistakes in Theory and Practice

Introduction

Error correction remains one of the most debated and emotionally charged practices in English Language Teaching (ELT). Language instructors routinely face the dilemma of whether, when, and how to correct learners without interrupting communication or undermining student confidence. However, before these practical decisions can be made responsibly, a more fundamental question must be addressed: What exactly is being corrected? As seminal research in Second Language Acquisition (SLA) has demonstrated, not all deviations from the target language are equal. Some of these deviations reflect temporary performance lapses, while others reveal deeper developmental processes inherent to language learning.

Stephen Pit Corder’s groundbreaking insight reframed learner errors not as signs of failure but as evidence of learning in progress. As Corder famously argued, “Errors are significant in three different ways. First, to the teacher, because they tell him how far towards the goal the learner has progressed” (Corder, 1967, p. 161). This reconceptualization laid the groundwork for later theories such as Selinker’s interlanguage hypothesis and Ellis’s extensive work on error analysis and corrective feedback.

This essay explores the theoretical distinction between errors and mistakes, examines their relevance to interlanguage development, and discusses the pedagogical implications for correction practices in Communicative Language Teaching (CLT) and Task-Based Language Teaching (TBLT). Additionally, the essay highlights how the Common European Framework of Reference for Languages (CEFR) provides a principled framework for interpreting learner errors developmentally rather than normatively.

Errors vs. Mistakes: A Foundational Distinction

One of the most enduring contributions of SLA research is the distinction between errors and mistakes. Corder (1967) clarified this difference by emphasizing learner competence rather than surface accuracy. He stated unequivocally: “It will be useful… to refer to errors of performance as mistakes” (p. 166). Mistakes, therefore, are unsystematic lapses caused by fatigue, distraction, or pressure, and they do not reflect gaps in the learner’s underlying linguistic system. Errors, in contrast, are systematic and reveal the learner’s current stage of linguistic development. As Corder explained, “Errors are systematic, i.e. likely to occur repeatedly and not recognized by the learner” (1967, p. 167). This distinction is crucial because it determines whether correction is necessary, useful, or even possible at a given moment.

Rod Ellis reinforces this perspective by arguing that “an error takes place when the deviation arises as a result of lack of knowledge” (Ellis, 1997, p. 17). From this viewpoint, errors are not random; they are rule-governed manifestations of a learner’s internal grammar. Correcting an error prematurely, without considering whether the learner is developmentally ready, may therefore be ineffective or counterproductive. In other words, learners will continue to make the same mistake without noticing their lack of mastery in the target language.

Errors as Evidence of Interlanguage Development

Larry Selinker’s concept of interlanguage provided a theoretical explanation for why learner errors are systematic and persistent. Selinker defined interlanguage as “a separate linguistic system based on the observable output which results from a learner’s attempted production of a target language norm” (Selinker, 1972, p. 214). This system is neither the learner’s first language nor the target language but a dynamic, evolving grammar of its own.

From this perspective, errors are not deviations from a fixed standard but indicators of transitional competence. Selinker further noted that “interlanguage systems are permeable, dynamic, and systematic” (1972, p. 215), emphasizing that change occurs gradually through hypothesis testing rather than immediate correction. Ellis supports this developmental view by asserting that “learners construct their own unique linguistic systems and these systems change over time” (Ellis, 2008, p. 51). Errors, then, are not obstacles to be eliminated but data points that reveal where learners are in their developmental learning path.

Fossilization vs. Developmental Error

One of the most challenging phenomena in error correction is fossilization. Selinker described fossilization as the process whereby “linguistic items, rules, and subsystems which speakers of a particular NL tend to keep in their interlanguage” become resistant to change (Selinker, 1972, p. 215). Unlike developmental errors, fossilized forms persist despite exposure, instruction, and feedback.

Ellis distinguishes these phenomena clearly, stating that “developmental errors are those that arise because learners have not yet mastered a particular target-language form, whereas fossilized errors are errors that learners have stopped trying to eliminate” (Ellis, 1997, p. 20). This distinction has direct pedagogical consequences: developmental errors often resolve themselves over time, while fossilized errors may require targeted, explicit intervention, if they can be addressed at all since learners may unconsciously neglect to pay attention to arears in the language where they are being corrected.

Pedagogical Implications: When Correction Helps—and When It Hurts

Understanding the nature of learner error fundamentally alters the teacher’s role. If errors are developmental, excessive correction may interrupt communication and raise anxiety without accelerating acquisition. Ellis warns that “there is no guarantee that corrective feedback will result in learning” (Ellis, 2008, p. 963), particularly when learners are not developmentally ready.

Conversely, ignoring all errors is equally problematic. Corder argued that errors are valuable precisely because “they provide evidence of how language is learned” (1967, p. 161). Teachers, therefore, must learn to diagnose errors rather than react reflexively to surface inaccuracies. This diagnostic stance aligns closely with communicative methodologies such as CLT and TBLT, where meaning takes precedence over form, but form is not abandoned altogether.

Error Correction in CLT and TBLT: A Comparative View

The table below highlights how the distinction between errors and mistakes informs correction practices in Communicative Language Teaching (CLT) and Task-Based Language Teaching (TBLT).

Aspect	CLT	TBLT
Primary focus	Meaningful communication	Task completion and outcome
Treatment of mistakes	Often ignored or briefly reformulated	Usually ignored during task
Treatment of errors	Selective correction post-activity	Addressed in post-task focus on form
Role of correction	Support fluency and confidence	Enhance accuracy after meaning
Teacher stance	Facilitator of communication	Analyst of task performance

Both approaches reflect Ellis’s assertion that “focus on form refers to any planned or incidental instructional activity that is intended to induce language learners to pay attention to linguistic form” (Ellis, 2001, p. 1). Crucially, such focus occurs after meaning has been negotiated, not during initial communication.

The Role of the CEFR in Interpreting Learner Error

The Common European Framework of Reference for Languages (CEFR) provides an essential macro-framework for understanding learner errors developmentally. Rather than treating errors as deviations from native-speaker norms, the CEFR emphasizes progression across proficiency levels. It explicitly states that “learners at different levels show different degrees of control over linguistic resources” (Council of Europe, 2001, p. 110).

This perspective legitimizes learner error as level-appropriate behavior. An A2 learner’s misuse of past tense forms, for instance, should not be judged by B2 standards. The CEFR further acknowledges that “errors are a natural manifestation of language learning” (Council of Europe, 2001, p. 153), reinforcing the SLA view that errors are developmental rather than defective. So, by aligning correction practices with CEFR descriptors, teachers can avoid overcorrection and instead focus on errors that impede intelligibility or fall within the learner’s zone of proximal development.

Conclusion

Distinguishing between errors and mistakes is not a semantic exercise but a foundational competence for effective ELT practice. As Corder, Selinker, and Ellis have demonstrated, learner errors are systematic, meaningful, and developmentally motivated. Treating all deviations as problems to be corrected ignores decades of SLA research and risks undermining both acquisition and learner confidence.

When teachers understand errors as evidence of interlanguage development, correction becomes a strategic, principled decision rather than an instinctive reaction. Within communicative frameworks such as CLT and TBLT, and guided by the CEFR’s developmental orientation, error correction can support both fluency and accuracy without sacrificing learner agency.

Ultimately, effective error correction begins not with how to correct, but with understanding what an error truly represents.

San José, Costa Rica

Friday, February 20, 2026

📚 References

Corder, S. P. (1967). The significance of learners’ errors. International Review of Applied Linguistics, 5(4), 161–170. https://eric.ed.gov/?id=ED019903

Council of Europe. (2001). Common European Framework of Reference for Languages: Learning, teaching, assessment. Cambridge University Press. https://rm.coe.int/common-european-framework-of-reference-for-languages-learning-teaching/16802fc1bf#:~:text=The%20aim%20of%20these%20notes,or%20as%20a%20member%20of

Ellis, R. (1997). Second language acquisition. Oxford University Press. https://escholarship.org/uc/item/3ch6f6tk

Ellis, R. (2001). Investigating form-focused instruction. Language Learning, 51(S1), 1–46. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-1770.2001.tb00013.x

Ellis, R. (2008). The study of second language acquisition (2nd ed.). Oxford University Press. https://es.scribd.com/document/715674871/Rod-Ellis-the-Study-of-Second-Language-Acquisition

Selinker, L. (1972). Interlanguage. International Review of Applied Linguistics, 10(3), 209–231. https://doi.org/10.1515/iral.1972.10.1-4.209

The Nature of Learner Error in ELT by Jonathan Acuña