Introduction

If I had a pound for every time I’ve heard “you must stay in the target language 100% of the time”, I’d probably be writing this from a beach somewhere rather than my desk; and yet, in my experience, as appealing as such slogans may appear—succinct, emphatic, and seemingly grounded in common sense—they tend, upon closer inspection, to unravel under the weight of empirical scrutiny.

Let me be clear from the outset: maximising target language (TL) use is pedagogically sound, and in my observation this is borne out both in the literature and in the classroom. A substantial body of research shows that frequent, meaningful exposure to the TL is essential for acquisition (Krashen, 1985; Nation, 2013; Ellis, 2015), since learners require rich input, repeated encounters, and opportunities to process language in context, all of which, when orchestrated judiciously, contribute to the gradual entrenchment of form–meaning mappings. In my own work with the EPI approach, I would argue that input is the engine of acquisition—and therefore the TL must dominate classroom discourse.

However—and this is the crucial point—“maximising TL” is not the same as “TL-only at all costs.”

In beginner, mixed-ability classrooms where all learners share the same L1, rigid TL-only policies can, in my experience, overwhelm working memory, reduce comprehension, increase anxiety, and ultimately disengage a significant proportion of learners, particularly when the linguistic demands exceed their current processing capacity and when no mediating support is available to stabilise meaning; and if that is the case, one might reasonably ask, what exactly are we maximising—exposure or confusion? In such contexts, the L1 is not the enemy of acquisition; it is a cognitive tool—a scaffold, a shortcut, and, dare one say (to use a slightly antiquated turn of phrase), a propedeutic aid.

Let’s unpack this properly, with the research in hand.

1. Comprehensibility: The Non-Negotiable Condition for Learning

One of the most robust findings in SLA is that input must be understood to be useful, a principle so well-established that it borders on the axiomatic. Nation (2013) and Hu & Nation (2000) suggest that learners need to know around 95–98% of the words in a text to process it effectively, which, in my experience, is rarely the case in beginner mixed-ability classrooms unless the input has been very carefully engineered.

In beginner classrooms, TL-only instruction often pushes learners well below this threshold, with the predictable consequence that comprehension falters and processing becomes superficial, fragmented, and at times illusory, as learners cling to isolated lexical items while failing to construct a coherent representation of meaning. The result?

• Guessing
• Shallow processing
• Cognitive overload
• Disengagement

A brief L1 clarification—ten seconds, no more—can restore comprehensibility and allow learners to actually process the TL input that follows, thereby ensuring that subsequent exposure is not merely auditory noise but cognitively tractable material.

As Nation (2013) reminds us, time spent not understanding is time not learning—and, if one may be permitted a rhetorical flourish, what conceivable virtue is there in incomprehension?

2. Cognitive Load

According to Cognitive Load Theory (Sweller, 2010), working memory is severely limited—typically handling around 4–6 elements at a time (Baddeley, 2000)—a constraint which, though often acknowledged in theory, is in my observation routinely underestimated in practice, particularly when teachers attempt to sustain extended TL-only discourse with novice learners.

Beginner learners are already juggling:

• New phonology
• New vocabulary
• New syntax

When we insist on delivering instructions and explanations exclusively in the TL, we often add extraneous cognitive load, that is to say, processing which does not directly contribute to schema construction but instead taxes limited attentional resources, thereby impeding rather than facilitating learning; and is it not somewhat paradoxical that, in striving to immerse learners in the TL, we may in fact be diminishing their capacity to process it?

The irony is stark: in trying to increase exposure, we may actually reduce effective processing.

A well-timed L1 explanation reduces this extraneous load, allowing learners to allocate their limited cognitive resources to what actually matters: processing the TL input—a point which, though seemingly self-evident, bears reiteration in the current climate of methodological absolutism.

3. Preventing Mislearning

VanPatten’s Input Processing theory (2015) shows that learners rely heavily on default strategies, such as prioritising content words and neglecting morphological markers, particularly when processing capacity is strained; and in my experience, this tendency is exacerbated in TL-only environments where meaning is insufficiently anchored.

And here’s the problem:
👉 Incorrectly learned language is harder to unlearn than correctly learned language is to acquire.

When comprehension is weak, learners generate incorrect form–meaning mappings, which, once established, may fossilise and resist subsequent correction, thereby creating a pedagogical impediment that is far more onerous to address than the initial misunderstanding.

Strategic L1 use can:

• Clarify meaning precisely
• Prevent faulty hypotheses
• Stabilise early representations

In other words, it acts as a quality control mechanism for input processing—an intervention not of indulgence but of prudence.

4. Efficiency and Time-on-Task

Macaro (2001) and Turnbull & Dailey-O’Cain (2009) both highlight that judicious L1 use increases efficiency, a finding which aligns closely with my own observation that time squandered on protracted TL explanations often yields diminishing returns, particularly in heterogeneous classrooms.

A concept that takes two minutes to explain in the TL may take ten seconds in the L1, and while some may argue that those two minutes constitute valuable exposure, one must ask whether such exposure, if only partially understood, is in fact pedagogically efficacious.

This is not about laziness—it is about optimising instructional time, or, to employ a somewhat recherché expression, ensuring economy of cognitive effort.

Every minute saved on clarification is a minute gained for:

• Input flood
• Processing tasks
• Retrieval practice

Ironically, less rigid TL use can result in more total TL exposure—a conclusion which, though counterintuitive to some, is well supported by both research and classroom praxis.

5. Affective Factors: Keeping Students in the Game

Krashen’s Affective Filter Hypothesis (1985) reminds us that anxiety, confusion, and low self-efficacy can block acquisition, and in my experience this is particularly salient in mixed-ability classrooms where weaker learners, unable to access meaning, may withdraw cognitively even if they remain physically present.

TL-only approaches often:

• Benefit the top 20%
• Marginalise the rest

Lower-attaining learners, unable to follow, disengage—not because they are unwilling, but because they are locked out of meaning, and once this disengagement sets in, it can be remarkably difficult to reverse, especially if learners begin to perceive the subject as impenetrable.

Research by Macaro (2005) and Levine (2011) shows that appropriate L1 use can reduce anxiety and increase participation, particularly in lower-proficiency learners, thereby lowering the affective filter and facilitating engagement with the TL input.

6. The Power of Cross-Linguistic Comparison

Ellis (2006) and Hall & Cook (2012) highlight the value of explicit comparison between L1 and L2, a process which, in my observation, not only enhances noticing but also accelerates the consolidation of form–meaning relationships, particularly when learners are guided to attend to subtle differences that might otherwise escape their attention.

The L1 provides a powerful reference point for:

• Noticing differences
• Avoiding negative transfer
• Deepening understanding

Example:

• Mi piace il calcio → “to me pleases football”

Without L1 mediation, this structure can remain opaque for a considerable period, whereas a brief contrastive explanation can render it immediately intelligible—mutatis mutandis, the same principle applies across numerous grammatical structures.

Used well, the L1 is not a crutch—it is a cognitive lever.

7. Code-Switching and the Bilingual Brain

From a psycholinguistic perspective, bilinguals do not “turn off” one language to use another; rather, research shows that both languages are co-activated in the brain (Kroll, Bobb & Wodniecka, 2006; Green & Abutalebi, 2013), a phenomenon which has significant implications for classroom practice, even if it is sometimes overlooked in methodological debates.

This means:

• The L1 is always present
• Learners naturally draw on it
• Suppressing it entirely is neither realistic nor cognitively optimal

Strategic code-switching:

• Reduces processing effort
• Facilitates meaning-making
• Supports lexical access

In other words, using the L1 aligns with how the brain actually works, and to ignore this is, arguably, to disregard a fundamental aspect of human cognition.

8. The Mixed-Ability Reality

Let us not indulge in pedagogical idealisation: in real classrooms, ability is not evenly distributed, and any approach that fails to account for this heterogeneity risks privileging a minority at the expense of the majority.

TL-only instruction often results in:

• Stronger learners inferring meaning
• Weaker learners copying or withdrawing

In my experience, strategic L1 use allows us to maintain inclusivity while preserving cognitive challenge, ensuring that all learners can access meaning without diluting the intellectual demands of the task, which, after all, remains firmly rooted in the TL.

So Where Does This Leave Us?

The research does not support:

• ❌ TL-only dogma
• ❌ Excessive reliance on L1

Instead, it supports a principled middle ground, one which, though less rhetorically appealing than absolutist positions, is far more consistent with both theory and practice:

• Maximise meaningful TL input
• Use L1 strategically and sparingly for:
  • Instructions
  • Clarification
  • Contrastive explanation
  • Repair

Final Thoughts

The real question is not:

“Should I use the TL or the L1?”

But rather—if I may phrase it thus—

“At this precise moment, what will maximise comprehension, minimise cognitive overload, and lead to better processing of the TL?”

If the answer is ten seconds of L1, then refusing to use it is not principled—it is ideological; and ideology, as we know, is a very poor substitute for learning. Whenever a staunch of TL-only starts giving me their spiel as to why it is so key that the teacher speak solely or 99% in the TL and that teaching resources are solely or 99% in the TL, I always ask the very same question: is there a chance that one student in the class is left behind? If so, then it is unethical. Period.

The L1 should be used as pedagogical capital, at the right time, in the right way in order to scaffold TL use. In EPI, for instance, this is achieved through gradually phasing out the L1 after a substantive input-to-output sequence where English is not spoken, but helps maintaining input-processing comprhensible and retrieval feasible.