{
  "title": "How Mandarin vowels and finals work",
  "date": "2026-10-20",
  "status": "Published reference",
  "scope": "Complete mapping of the current 39 Sound Lab final IDs, not a universal inventory of Mandarin vowel phonemes.",
  "sources": [
    {
      "id": "ipa",
      "title": "International Phonetic Association — vowel chart",
      "url": "https://www.internationalphoneticassociation.org/IPAcharts/common_files/pdfs/pdfs_IPA_charts_E/IPA_unitipa_V.pdf",
      "use": "Authoritative classification vocabulary; not a Mandarin-specific inventory."
    },
    {
      "id": "uw",
      "title": "University of Washington — Mandarin vowel chart",
      "url": "https://courses.washington.edu/chin342/ipa/vowels.html",
      "use": "Pinyin/IPA and audio. Explicitly places Mandarin a centrally in its teaching chart."
    },
    {
      "id": "lee",
      "title": "Lee & Zee (2003) — Standard Chinese (Beijing)",
      "url": "https://www.cambridge.org/core/services/aop-cambridge-core/content/view/050A393AF2D3C325E3C6796FE8CA99A3/S0025100303001208a.pdf/standard_chinese_beijing.pdf",
      "use": "Primary phonetic description, pp. 110–111: context-dependent vowels, glides and syllabic consonants. Describes a Beijing model, not every speaker."
    },
    {
      "id": "polyu-simple",
      "title": "Hong Kong Polytechnic University — simple finals",
      "url": "https://www.polyu.edu.hk/bepth/introduction-to-phonetics/simple-finals/?sc_lang=en",
      "use": "Useful listening models and o/uo discussion. English analogies are approximations, not definitions."
    },
    {
      "id": "polyu-groups",
      "title": "Hong Kong Polytechnic University — compound final groups",
      "url": "https://www.polyu.edu.hk/bepth/introduction-to-phonetics/compound-finals/compound-final-groups/",
      "use": "Grouping, ian, anticipatory rounding in iong, and variable prominence in iou/uei."
    },
    {
      "id": "polyu-structure",
      "title": "Hong Kong Polytechnic University — compound-final structure",
      "url": "https://www.polyu.edu.hk/bepth/introduction-to-phonetics/compound-finals/introduction-to-compound-finals/?sc_lang=en",
      "use": "Main vowel versus other components; distinguishes the two nasal endings."
    },
    {
      "id": "polyu-spelling",
      "title": "Hong Kong Polytechnic University — Pinyin spelling",
      "url": "https://www.polyu.edu.hk/bepth/introduction-to-phonetics/spelling-rules-in-pinyin/?sc_lang=en",
      "use": "Canonical iou/uei/uen, written iu/ui/un, and ü spelling after j/q/x/y."
    },
    {
      "id": "osu",
      "title": "Ohio State University — Mandarin IPA charts",
      "url": "https://ielp.ehe.osu.edu/files/2025/09/IPA_Mandarin.pdf",
      "use": "Oral and nasal-context vowel charts, including [ʊ] in ong and fronted vowels in ian. PDF chart headings/IPA versus Pinyin labeling require care; cross-check symbols rather than copying automatically."
    },
    {
      "id": "air",
      "title": "Catherine Anderson — Essentials of Linguistics: Articulators",
      "url": "https://pressbooks.pub/essentialsoflinguistics/chapter/2-3-articulators/",
      "use": "General articulatory mechanism: lungs, vocal folds, oral closure and velum/nasal passage."
    },
    {
      "id": "rhotic",
      "title": "Chen, Whalen & Mok (2024) — Mandarin rhotics",
      "url": "https://ling.cuhk.edu.hk/people/peggy/ChenWhalenMok_2024_MandarinR.pdf",
      "use": "Ultrasound study of 18 speakers; syllabic/postvocalic rhotics include tip-up and tip-down bunched shapes."
    },
    {
      "id": "apical",
      "title": "Huang, Hsieh & Chang (2021) — cross-dialectal apical vowels",
      "url": "https://www.isca-archive.org/interspeech_2021/huang21i_interspeech.html",
      "use": "EMA/ultrasound evidence that apical-vowel tongue configurations vary across Mandarin dialects."
    },
    {
      "id": "four",
      "title": "Qingdao University of Technology — phonetic concepts",
      "url": "https://jw.qut.edu.cn/info/1087/1705.htm",
      "use": "Traditional 四呼 categories based on the beginning of the final."
    },
    {
      "id": "four-exceptions",
      "title": "Shanxi Finance & Taxation College — 四呼 distinctions",
      "url": "https://www.sxftc.edu.cn/cjc/info/1228/3000.htm",
      "use": "Explicitly contrasts spelling-based versus articulatory placement of ong and iong."
    },
    {
      "id": "yo",
      "title": "Taiwan Ministry of Education — 唷 yō",
      "url": "https://dict.revised.moe.edu.tw/dictView.jsp?ID=10762&la=1&powerMode=0",
      "use": "Attests the uncommon ㄧㄛ / yo syllable. Does not specify a narrow IPA tongue trajectory."
    },
    {
      "id": "glides",
      "title": "ChineseFor.Us — compound and nasal finals",
      "url": "https://chinesefor.us/lessons/chinese-pinyin-compound-finals-quiz/",
      "use": "Teacher-authored guidance: offglides are lighter than the main vowel, not separate full vowels."
    },
    {
      "id": "litao",
      "title": "Litao Chinese — Pinyin course syllabus",
      "url": "https://litaochinese.com/product/chinese-pinyin-course/",
      "use": "Primary provider descriptions for the five linked lessons and their target finals."
    },
    {
      "id": "iowa",
      "title": "Huiqiang Zheng / University of Iowa — Mastering Mandarin Sounds",
      "url": "https://pressbooks.uiowa.edu/zheng/",
      "use": "Supplementary activities and video collection. Some explanations are simplified; do not adopt literal letter-by-letter articulation or a universal fixed tongue position."
    },
    {
      "id": "lmu",
      "title": "LMU Munich — Mandarin language demonstration",
      "url": "https://www.phonetik.uni-muenchen.de/studium/skripten/languagedemos/Demos/mandarin.html",
      "use": "Audio-oriented introduction to ordinary vowels, apical syllabic sounds and rhotacization."
    }
  ],
  "videos": [
    {
      "id": "grace-vowels",
      "creator": "Grace Mandarin Chinese",
      "title": "Master Chinese Vowels — i, u, ü, a, o",
      "url": "https://www.youtube.com/watch?v=NVAJT-Itj00",
      "targets": [
        "i",
        "u",
        "ü",
        "a",
        "o"
      ],
      "use": "Lesson topic: comparing vowel positions and visible lip shapes."
    },
    {
      "id": "grace-nasals",
      "creator": "Grace Mandarin Chinese",
      "title": "Master Chinese Pronunciation — en eng / in ing / an ang",
      "url": "https://www.youtube.com/watch?v=4x51--A625g",
      "targets": [
        "en",
        "eng",
        "in",
        "ing",
        "an",
        "ang"
      ],
      "use": "Lesson topic: contrasting the nasal-final families."
    },
    {
      "id": "litao-basic",
      "creator": "Learn Chinese with Litao",
      "title": "Pinyin Lesson 01 — simple finals and tones",
      "url": "https://www.youtube.com/watch?v=krO-A8L47UI",
      "targets": [
        "a",
        "o",
        "e",
        "i",
        "u",
        "ü",
        "er"
      ],
      "use": "Provider lists the six common simple finals plus er and tone/spelling practice."
    },
    {
      "id": "litao-glides",
      "creator": "Learn Chinese with Litao",
      "title": "Pinyin Lesson 07 — nine diphthong finals",
      "url": "https://www.youtube.com/watch?v=8l4KVE-VBh0",
      "targets": [
        "ao",
        "ai",
        "ou",
        "ei",
        "ie",
        "ia",
        "ua",
        "uo",
        "üe"
      ],
      "use": "Provider lists nine moving vowel finals."
    },
    {
      "id": "litao-triples",
      "creator": "Learn Chinese with Litao",
      "title": "Pinyin Lesson 08 — four triphthong finals",
      "url": "https://www.youtube.com/watch?v=ZS-2bK2j8VU",
      "targets": [
        "iao",
        "iou",
        "uai",
        "uei"
      ],
      "use": "Provider lists all four three-part glide patterns and contractions."
    },
    {
      "id": "litao-nasals",
      "creator": "Learn Chinese with Litao",
      "title": "Pinyin Lesson 09 — eight nasal simple finals",
      "url": "https://www.youtube.com/watch?v=VLr8ZJu6ko0",
      "targets": [
        "an",
        "ang",
        "en",
        "eng",
        "in",
        "ing",
        "ün",
        "ong"
      ],
      "use": "Provider lists the eight basic nasal finals."
    },
    {
      "id": "litao-compound",
      "creator": "Learn Chinese with Litao",
      "title": "Pinyin Lesson 10 — eight nasal compound finals",
      "url": "https://www.youtube.com/watch?v=Djo9v7fciO8",
      "targets": [
        "ian",
        "iang",
        "uan",
        "uang",
        "uen",
        "ueng",
        "üan",
        "iong"
      ],
      "use": "Provider lists the eight nasal finals with leading glides."
    }
  ],
  "finals": [
    {
      "id": "a",
      "ipa": "a ~ ɑ",
      "classification": "Simple oral vowel: open, central/back, unrounded",
      "cue": "Lower the tongue; open the jaw comfortably; leave the lips unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "uw",
        "ipa"
      ],
      "note": "Position varies with the final; avoid one fixed a shape everywhere.",
      "videoIds": [
        "grace-vowels",
        "litao-basic"
      ]
    },
    {
      "id": "o",
      "ipa": "o ~ ɔ; often wo-like after b/p/m/f",
      "classification": "Rounded mid/back vowel; context may include a short glide",
      "cue": "Round the lips and raise the back of the tongue moderately.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-simple",
        "uw"
      ],
      "note": "A pure o teaching target and contextual uo-like realizations should both be explained.",
      "videoIds": [
        "grace-vowels",
        "litao-basic"
      ]
    },
    {
      "id": "e",
      "ipa": "ɤ",
      "classification": "Simple oral vowel: close-mid back unrounded",
      "cue": "Keep the tongue body back and moderately raised; release lip rounding.",
      "airflow": "oral",
      "sourceIds": [
        "uw",
        "polyu-simple"
      ],
      "note": "Standalone e differs from e in en, ei, ie and üe; it may have slight internal movement.",
      "videoIds": [
        "litao-basic"
      ]
    },
    {
      "id": "i",
      "ipa": "i",
      "classification": "Simple oral vowel: close front unrounded",
      "cue": "Keep the tip low; raise the front tongue without sealing the passage; lips unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "uw",
        "ipa"
      ],
      "note": "Ordinary i as in mi; not the finals of zi or zhi.",
      "videoIds": [
        "grace-vowels",
        "litao-basic"
      ]
    },
    {
      "id": "u",
      "ipa": "u",
      "classification": "Simple oral vowel: close back rounded",
      "cue": "Raise the back of the tongue; round the lips, with a small comfortable opening.",
      "airflow": "oral",
      "sourceIds": [
        "uw",
        "ipa"
      ],
      "note": "Do not add an extra consonant or force tight lips.",
      "videoIds": [
        "grace-vowels",
        "litao-basic"
      ]
    },
    {
      "id": "ü",
      "ipa": "y",
      "classification": "Simple oral vowel: close front rounded",
      "cue": "Keep the front of the tongue high and forward as for i, then round the lips.",
      "airflow": "oral",
      "sourceIds": [
        "uw",
        "polyu-simple"
      ],
      "note": "IPA y is a vowel symbol. Written u after j/q/x and in yu belongs to this family.",
      "videoIds": [
        "grace-vowels",
        "litao-basic"
      ]
    },
    {
      "id": "er",
      "ipa": "ɚ",
      "classification": "Rhotic vowel: r-colored, commonly central",
      "cue": "Keep voicing. One option gently raises the tip behind the upper ridge without touching; another bunches the tongue body with the tip down. Keep an open passage.",
      "airflow": "oral",
      "sourceIds": [
        "rhotic",
        "lmu"
      ],
      "note": "Tip-up and bunched tongue shapes are both documented. Erhua changes a preceding final; it is not always an added er syllable. The lab illustrates a bunched configuration.",
      "videoIds": [
        "litao-basic"
      ]
    },
    {
      "id": "i-front",
      "ipa": "ɹ̩ (one analysis)",
      "classification": "Special syllabic sound after z/c/s; traditionally apical vowel",
      "cue": "Keep the front constriction near the upper teeth/ridge; continue voicing with reduced friction.",
      "airflow": "oral",
      "sourceIds": [
        "lee",
        "apical"
      ],
      "note": "Not ordinary i. Traditional ɿ is not a standard IPA vowel symbol; no English-r instruction is intended.",
      "videoIds": []
    },
    {
      "id": "i-back",
      "ipa": "ɻ̩ (one analysis)",
      "classification": "Special syllabic sound after zh/ch/sh/r; traditionally apical vowel",
      "cue": "Retain a comfortable postalveolar tongue configuration while continuing the voiced syllable.",
      "airflow": "oral",
      "sourceIds": [
        "lee",
        "apical"
      ],
      "note": "Not ordinary i or identical to er. Traditional ʅ and alternative syllabic transcriptions reflect different analyses.",
      "videoIds": []
    },
    {
      "id": "ai",
      "ipa": "aɪ̯",
      "classification": "Closing diphthong: open toward high front",
      "cue": "Begin relatively open; raise the front tongue as the jaw narrows; lips remain unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "glides",
        "lee"
      ],
      "note": "The ending is brief and need not reach a full sustained i.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ei",
      "ipa": "ei̯ ~ eɪ̯",
      "classification": "Closing diphthong: mid-front toward high front",
      "cue": "Begin with a mid-front vowel; raise the front tongue slightly; keep lips unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "glides",
        "uw"
      ],
      "note": "Its starting e is not standalone back e [ɤ].",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ao",
      "ipa": "ɑʊ̯",
      "classification": "Closing diphthong: open/back toward high/back rounded",
      "cue": "Begin low and open; lift the back tongue and increase rounding toward the end.",
      "airflow": "oral",
      "sourceIds": [
        "glides",
        "lee"
      ],
      "note": "The spelling o does not require stopping at an isolated o vowel.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ou",
      "ipa": "ou̯ ~ oʊ̯",
      "classification": "Closing diphthong: mid/back rounded toward higher/back",
      "cue": "Start rounded; narrow the jaw and lip opening as the back tongue rises.",
      "airflow": "oral",
      "sourceIds": [
        "glides",
        "lee"
      ],
      "note": "Keep one syllable; the second portion is lighter.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ia",
      "ipa": "ja",
      "classification": "Leading front glide plus open vowel",
      "cue": "Start high/front and move promptly to a low tongue and open jaw; lips unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "lee"
      ],
      "note": "IPA j means the y-like glide, not Pinyin j.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ie",
      "ipa": "jɛ ~ je̞",
      "classification": "Leading front glide plus front mid/open-mid vowel",
      "cue": "From high/front, lower the front tongue moderately and open the jaw; lips unrounded.",
      "airflow": "oral",
      "sourceIds": [
        "osu",
        "lee"
      ],
      "note": "Finish at a front vowel, not standalone back e.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "ua",
      "ipa": "wa",
      "classification": "Leading back rounded glide plus open vowel",
      "cue": "Start with u-like rounding; lower the tongue and open/unround toward a.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "lee"
      ],
      "note": "The opening glide is brief; avoid two syllables.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "uo",
      "ipa": "wo ~ wɔ",
      "classification": "Leading back rounded glide plus mid/back rounded vowel",
      "cue": "Start high/back rounded; open the jaw moderately and lower the back tongue; keep rounding.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-simple",
        "lee"
      ],
      "note": "Finish more open than u; do not return to u at the end.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "üe",
      "ipa": "ɥɛ ~ ɥe̞",
      "classification": "Leading front rounded glide plus front mid/open-mid vowel",
      "cue": "Begin ü-like, then lower the front tongue and relax rounding toward the final vowel.",
      "airflow": "oral",
      "sourceIds": [
        "osu",
        "lee"
      ],
      "note": "Written yue, jue, que, xue retain the ü-family glide.",
      "videoIds": [
        "litao-glides"
      ]
    },
    {
      "id": "io",
      "ipa": "jo",
      "classification": "Uncommon leading front glide plus rounded mid/back vowel",
      "cue": "Move from a brief front glide toward an o-like vowel, adding rounding.",
      "airflow": "oral",
      "sourceIds": [
        "yo",
        "uw"
      ],
      "note": "Uncommon final in yo. The lab illustrates a front glide into an o-like vowel; exact realization varies by speaker.",
      "videoIds": []
    },
    {
      "id": "iao",
      "ipa": "jɑʊ̯",
      "classification": "Leading front glide plus closing diphthong",
      "cue": "Move high/front → low/open → higher/back with increasing rounding at the finish.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "litao"
      ],
      "note": "One syllable; the opening glide and ending are lighter than the middle.",
      "videoIds": [
        "litao-triples"
      ]
    },
    {
      "id": "iou",
      "ipa": "jou̯",
      "classification": "Leading front glide plus rounded closing diphthong",
      "cue": "Move from a front glide into a rounded mid/back vowel, then close slightly.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "litao"
      ],
      "note": "Usually written iu after an initial; middle-vowel prominence varies.",
      "videoIds": [
        "litao-triples"
      ]
    },
    {
      "id": "uai",
      "ipa": "waɪ̯",
      "classification": "Leading rounded back glide plus front-closing diphthong",
      "cue": "Begin rounded/high-back, open toward a, then raise the front tongue; unround.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "litao"
      ],
      "note": "One continuous syllable, not three equally stressed vowels.",
      "videoIds": [
        "litao-triples"
      ]
    },
    {
      "id": "uei",
      "ipa": "wei̯",
      "classification": "Leading rounded back glide plus front-closing diphthong",
      "cue": "Begin u-like; move toward mid-front e then higher/front i, releasing rounding.",
      "airflow": "oral",
      "sourceIds": [
        "polyu-groups",
        "litao"
      ],
      "note": "Usually written ui after an initial; middle-vowel prominence varies.",
      "videoIds": [
        "litao-triples"
      ]
    },
    {
      "id": "an",
      "ipa": "an",
      "classification": "Open unrounded vowel plus front nasal",
      "cue": "Begin low; close with the tongue tip/front at the upper teeth/ridge; lips unrounded.",
      "airflow": "n",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "The nasal ending is voiced; no added vowel afterward.",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "en",
      "ipa": "ən",
      "classification": "Mid-central unrounded vowel plus front nasal",
      "cue": "Keep a relaxed central vowel, then close at the upper teeth/ridge with the tongue front.",
      "airflow": "n",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "Use central schwa, not a full standalone e [ɤ].",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "in",
      "ipa": "in",
      "classification": "High-front unrounded vowel plus front nasal",
      "cue": "Hold an i-like body position; bring the tongue front to the upper teeth/ridge.",
      "airflow": "n",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "The closure differentiates in from ing; preserve one syllable.",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "ian",
      "ipa": "jɛn ~ jæn",
      "classification": "Front glide plus front mid/low vowel plus front nasal",
      "cue": "Start i-like; lower toward an open front vowel; finish with the front-tongue nasal closure.",
      "airflow": "n",
      "sourceIds": [
        "polyu-groups",
        "osu"
      ],
      "note": "The a is higher/fronted relative to standalone a; avoid mechanically joining i and an.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "uan",
      "ipa": "wan",
      "classification": "Rounded back glide plus open vowel plus front nasal",
      "cue": "Start rounded; open and unround toward a; finish with the front-tongue nasal closure.",
      "airflow": "n",
      "sourceIds": [
        "polyu-groups",
        "air"
      ],
      "note": "Distinct from üan despite similar spelling after j/q/x.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "uen",
      "ipa": "wən",
      "classification": "Rounded back glide plus central vowel plus front nasal",
      "cue": "Start rounded/high-back; relax toward central schwa; finish with the front-tongue closure.",
      "airflow": "n",
      "sourceIds": [
        "polyu-groups",
        "air"
      ],
      "note": "Usually written un after an initial; not the ün of jun/qun/xun/yun.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "üan",
      "ipa": "ɥɛn ~ ɥæn",
      "classification": "Rounded front glide plus front vowel plus front nasal",
      "cue": "Start ü-like; open toward a front vowel and relax rounding; close with the tongue front.",
      "airflow": "n",
      "sourceIds": [
        "polyu-groups",
        "osu"
      ],
      "note": "Written yuan, juan, quan, xuan; the nucleus is not plain back/open a.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "ün",
      "ipa": "yn",
      "classification": "High-front rounded vowel plus front nasal",
      "cue": "Keep ü-like tongue position and rounded lips; bring the tongue front into nasal closure.",
      "airflow": "n",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "Written yun or un after j/q/x; do not substitute u.",
      "videoIds": [
        "litao-nasals"
      ]
    },
    {
      "id": "ang",
      "ipa": "ɑŋ",
      "classification": "Open back unrounded vowel plus back nasal",
      "cue": "Begin low/back with an open jaw; raise the tongue back to the soft palate.",
      "airflow": "ng",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "The vowel often differs from an as well as the closure.",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "eng",
      "ipa": "əŋ ~ ɤŋ",
      "classification": "Central/back mid unrounded vowel plus back nasal",
      "cue": "Begin with an unrounded mid vowel; raise the back of the tongue into nasal closure.",
      "airflow": "ng",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "Sources/speakers differ in the nucleus; do not insist on one exact e height.",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "ing",
      "ipa": "iŋ ~ iəŋ",
      "classification": "High-front unrounded vowel plus back nasal",
      "cue": "Start i-like; form the ending closure with the tongue back, keeping the tip low.",
      "airflow": "ng",
      "sourceIds": [
        "osu",
        "air"
      ],
      "note": "A central transition may be audible; do not add a separate syllable.",
      "videoIds": [
        "grace-nasals",
        "litao-nasals"
      ]
    },
    {
      "id": "ong",
      "ipa": "ʊŋ ~ uŋ",
      "classification": "High/near-high back rounded vowel plus back nasal",
      "cue": "Start high/back with rounded lips, somewhat relaxed; close at the soft palate.",
      "airflow": "ng",
      "sourceIds": [
        "osu",
        "lee"
      ],
      "note": "Its vowel is higher than ordinary o; the written letter is not the articulation.",
      "videoIds": [
        "litao-nasals"
      ]
    },
    {
      "id": "iang",
      "ipa": "jɑŋ",
      "classification": "Front glide plus open/back vowel plus back nasal",
      "cue": "Start high/front; open toward a low vowel; finish with back-tongue nasal closure.",
      "airflow": "ng",
      "sourceIds": [
        "polyu-groups",
        "air"
      ],
      "note": "Contrast ian using both vowel quality and closure location.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "uang",
      "ipa": "wɑŋ",
      "classification": "Rounded back glide plus open/back vowel plus back nasal",
      "cue": "Begin rounded; open toward a low vowel, easing rounding; close with the tongue back.",
      "airflow": "ng",
      "sourceIds": [
        "polyu-groups",
        "air"
      ],
      "note": "Do not keep the whole final at the u position.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "ueng",
      "ipa": "wəŋ",
      "classification": "Rounded back glide plus central vowel plus back nasal",
      "cue": "Begin u-like; ease toward a central mid vowel; finish with back-tongue closure.",
      "airflow": "ng",
      "sourceIds": [
        "polyu-groups",
        "air"
      ],
      "note": "Typically the zero-initial spelling weng; distinguish from ong.",
      "videoIds": [
        "litao-compound"
      ]
    },
    {
      "id": "iong",
      "ipa": "jʊŋ ~ yŋ",
      "classification": "Front/rounded onset and rounded high vowel plus back nasal",
      "cue": "Round early; begin with a forward tongue position, then form the back nasal closure.",
      "airflow": "ng",
      "sourceIds": [
        "polyu-groups",
        "osu"
      ],
      "note": "Descriptions include glide-plus-back-rounded and front-rounded realizations. The lab illustrates early rounding followed by a relaxed back-rounded vowel and ng closure.",
      "videoIds": [
        "litao-compound"
      ]
    }
  ],
  "edition": "2026-10-20",
  "airflow": {
    "oral": "Voice and ordinary outward breath continue through the mouth; the nasal route is closed for the oral vowel.",
    "n": "The tongue front closes near the upper teeth/ridge; the velum opens the nasal route. Voice continues through the nose.",
    "ng": "The tongue back closes at the soft palate; the velum opens the nasal route. Voice continues through the nose, without an extra g release."
  },
  "teachingNote": "Broad teaching models: individual speakers and surrounding sounds affect the precise posture. A nasal transition can begin before complete oral closure."
}