When should a learner hear “Try that /θ/ again” — right after the slip or hours later during a recap? Timing shapes how well feedback sticks, how quickly habits shift, and even how motivated learners stay. Below is a research‑backed dive into why immediacy matters, when delay can outperform, and how 2025‑era AI finally lets us blend both without extra teacher load.

What We Mean by “Real‑Time” and “Delayed”

Most classroom correction falls into near‑immediate. Pure RTF became practical only once low‑latency ASR dropped < 200 ms in 2024 (e.g., GPT‑4o‑speech).

Why Timing Changes Uptake

1. Noticing & Phonological Encoding
   Schmidt’s Noticing Hypothesis (1990) says learners must notice gaps to change form. RTF highlights the gap while the articulatory plan is still buffer‑resident, boosting awareness.
2. Motor Memory Consolidation
   Practice within 30 s of an error re‑engages the same neuromuscular circuits (Fitts & Posner, 1967), accelerating muscle adjustment — crucial for segmental fixes like /ɹ/.
3. Cognitive Load & Flow
   Too‑frequent RTF can overload working memory, breaking communicative flow (Long, 2022 JSLP). Delayed summaries ease load but risk fossilization if the learner forgets the exact slip.

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What the Data Says (2020‑2025)

Li & Chen (2023)
Title: The effectiveness of automatic speech recognition in ESL/EFL pronunciation: A meta-analysis
DOI: https://doi.org/10.1017/S0958344023000196
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Key Findings:

• Meta-analysis of 42 studies comparing real-time vs delayed feedback in ASR-based pronunciation tools.
• Real-time feedback showed a mean effect size of g = 0.64, compared to g = 0.39 for delayed feedback.
• Tools with immediate intelligibility-focused cues outperformed those offering only end-of-task recaps.
• ASR-based systems were most effective when paired with segmental practice and immediate correction.

Luo et al. (2024)
Title: Real-time corrective feedback in mobile-assisted pronunciation training: Effects on English vowel duration
DOI: https://doi.org/10.1080/09588221.2024.2422478

Key Findings:

• Chinese EFL learners using a mobile app with real-time feedback improved vowel duration by 18% over four weeks.
• Control group receiving only delayed teacher feedback improved by 7%.
• Real-time feedback triggered faster self-monitoring and correction of segmental timing.
• Learners reported that immediate visual feedback (waveforms + color cues) was more motivating than teacher summaries.

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Sonsaat-Hegelheimer & Kurt (2025)
Title: The impact of generative AI-powered chatbots on L2 comprehensibility
DOI: https://doi.org/10.1075/jslp.24053.son

Key Findings:

• Pronounce users received utterance-level feedback immediately after speaking; Gemini users saw only live transcripts.
• Learners who received near-immediate feedback plus reflection (Pronounce + researcher guidance) showed the strongest retention.
• Delayed-only feedback (Gemini) raised awareness but didn’t lead to consistent uptake or correction.
• Blending timing — prompt cue + post-session reflection — was most effective for habit change.
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When Delayed Feedback Wins

1. High-Cognitive-Load Tasks

Why delay? Learners need every ounce of working-memory to plan meaning and syntax. An interruption forces them to juggle content + correction, so retention drops.
Pronunciation example: During a role-play sales call, let the speaker finish. Provide a timestamped note pack afterward so they can review without the pressure of real-time fixes.

2. Long-Form Output (stories, presentations, debates)

Why delay? Stopping mid-speech breaks fluency and discourse cohesion. Delayed feedback preserves the flow and gives you more data to comment on patterns, not one-off slips.
Example: After a five-minute story retell, the teacher records audio comments or inserts markers in the transcript instead of interrupting.

3. Affective-Filter Management

Why delay? Some learners freeze or feel judged when corrected on the spot. A short wait lowers anxiety, so feedback is processed instead of resisted.
Example: A shy student records a pitch; Pronounce AI emails a color-coded heat-map afterward rather than flashing live error beeps.

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Cognitive Load vs. Emotion

Below is a quick comparison of how each timing format affects key factors.

Best‑of‑Both: The 2025 Hybrid Loop

1. RTF for high‑frequency / high‑impact errors (think /θ/, /ð/, final‑consonant deletion).
2. Micro‑delay (5‑10 s) for intonation chunks — keeps flow but preserves recency.
3. Daily AI‑generated recap — an email or app card that embeds waveforms, IPA, and spaced‑repetition drills for the day’s top five errors.

Designing Courses Around Timing

• Flip it — Let AI handle RTF drills at home; use class for communicative tasks where teacher gives holistic delayed feedback.
• Reflection slots — Build 5‑minute “error journaling” breaks so delayed feedback still benefits from fresh memory.
• Personalize thresholds — Confident speakers? Push more RTF. High‑anxiety? Scale back and batch.

Key Takeaways

1. Choose feedback timing to fit the task. Drills thrive on instant cues; free speech benefits from post-hoc reflection.
2. Minimize cognitive overload. Keep live interruptions under two seconds and visually unobtrusive.
3. Schedule a rapid debrief. Even a 3-minute recap cements gains and fosters self-monitoring.
4. Leverage automation. Tools like Pronounce AI can deliver both streams without extra teacher workload.