Backsliding

Backsliding is the reappearance of interlanguage errors that appeared to have been eradicated. Selinker (1972) identified it as one of the defining characteristics of interlanguage: a learner demonstrates correct usage of a form, then reverts to a previous incorrect form, typically under communicative pressure.

Characteristics

Selinker (1972) argued that backsliding is neither random nor a simple return to the L1. It gravitates toward an interlanguage norm, a stable point in the learner's own system rather than the native language baseline. This distinguishes it from raw transfer.

Backsliding is most visible when:

• The learner is tired, stressed, or emotionally engaged
• Communication demands exceed the learner's processing capacity
• Attention shifts from form to meaning (unmonitored speech)
• The task requires real-time production under time pressure

Diagnostic Value

Backsliding reveals the gap between controlled and automatic knowledge. A learner who produces correct forms only when consciously monitoring, and reverts to errors in spontaneous speech, has not achieved automaticity for that feature. The correct form exists in explicit knowledge but has not been proceduralised.

This has important implications for assessment: a learner's best performance (careful, monitored output) may overestimate their actual acquisition level. Unmonitored production is a truer indicator of what has been fully acquired.

Backsliding vs Fossilization

	Backsliding	Fossilization
Nature	Temporary reappearance of errors	Permanent cessation of development
Trigger	Communicative pressure, fatigue, attention shift	Systematic: errors persist regardless of conditions
Prognosis	Correct form can be restored with attention	Resistant to instruction and feedback
Implication	Incomplete automatisation	Feature may never be fully acquired

Persistent backsliding over extended periods may be an early indicator of incipient fossilization, particularly if corrective feedback produces only temporary improvement.

Teaching Implications

• Backsliding under communicative pressure is normal and expected; it does not mean the learner has "unlearned" the form
• Activities should include both accuracy-focused practice and fluency tasks to promote automatisation
• Repeated backsliding on the same feature signals the need for further proceduralisation, not simply more rule explanation
• Assessment should sample both careful and spontaneous production

References

• Selinker, L. (1972). Interlanguage. International Review of Applied Linguistics, 10(3), 209–231.