{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/hear-the-contrast-across-different-voices",
  "id": "MHC-D-RESEARCH-1070",
  "version": "0.1.0",
  "title": "Hear the contrast across different voices",
  "summary": "Learning one recording is not the same as learning to hear a sound.",
  "kind": "protocol",
  "body": "Use several speakers to practise identifying a troublesome contrast. Keep the listening task separate from saying the sound yourself: perceptual research cannot promise automatic pronunciation gains.",
  "limits": [
    "Use reliable labels and comfortable volume. If the issue is recording quality or hearing difficulty, more drills may target the wrong problem."
  ],
  "topics": [
    "language-transfer-50"
  ],
  "intents": [],
  "source_ids": [
    "RS-7618F357A98A4239",
    "RS-FCC1FEB8AA33960A"
  ],
  "evidence": [
    {
      "claim": "High-variability phonetic training studies support improvements in L2 speech perception; the outcome is not interchangeable with pronunciation.",
      "source_id": "RS-7618F357A98A4239",
      "role": "supports",
      "note": "Voice diversity alone does not specify a complete effective programme.",
      "locator": "Abstract and discussion."
    },
    {
      "claim": "The Mandarin production study does not justify assuming that perceptual training automatically improves speech production.",
      "source_id": "RS-FCC1FEB8AA33960A",
      "role": "limits",
      "note": "Language-specific evidence; this is a limit on transfer, not a universal null result.",
      "locator": "Abstract, production results."
    }
  ],
  "use_when": [
    "You recognise a sound in one lesson but lose it when another person speaks."
  ],
  "avoid_when": [
    "Use reliable labels and comfortable volume. If the issue is recording quality or hearing difficulty, more drills may target the wrong problem."
  ],
  "example": "You distinguish ship from sheep in a familiar lesson, then test whether that distinction survives a different voice and sentence.",
  "check": "Record accuracy on unseen audio, not only on clips you have rehearsed.",
  "steps": [
    "Choose one contrast and labelled recordings from several speakers.",
    "Identify each item before revealing its label; replay mistakes with feedback.",
    "Check new words from an unfamiliar speaker, without written clues."
  ],
  "sources": [
    {
      "id": "RS-7618F357A98A4239",
      "title": "High variability phonetic training (HVPT): A meta-analysis of L2 perceptual training studies",
      "url": "https://www.cambridge.org/core/journals/studies-in-second-language-acquisition/article/high-variability-phonetic-training-hvpt-a-metaanalysis-of-l2-perceptual-training-studies/6ABB8C1F32D88D53EA8D05A4565E76F6"
    },
    {
      "id": "RS-FCC1FEB8AA33960A",
      "title": "Do Explicit Instruction and High Variability Phonetic Training Improve Nonnative Speakers’ Mandarin Tone Productions?",
      "url": "https://doi.org/10.1111/modl.12619"
    }
  ],
  "relations": [
    {
      "from": "MHC-D-RESEARCH-1070",
      "to": "MHC-D-RESEARCH-1071",
      "type": "useful_with",
      "url": "/knowledge/use-captions-then-check-what-your-ears-understood"
    }
  ],
  "collections": [
    {
      "id": "RC-E90A0EE1DFD29BBF",
      "title": "Language that survives a new situation",
      "url": "/collections/language-that-survives-a-new-situation"
    }
  ]
}