{
  "name": "Vocabulary size estimates by word definition, age and percentile: Brysbaert et al. (2016) and earlier studies",
  "desc": "Vocabulary size estimates by word definition, age and percentile. One row per value: the 2016 test's estimates for native speakers of American English by age and percentile (Table 4), the median shares of each list, the earlier adult estimates listed in the paper's Table 3 (as reported there; the originals were not read), and values recomputed by this site. Data from Brysbaert, Stevens, Mandera & Keuleers (2016), licensed CC BY 4.0; modified: one row per value in this site's own column order, numbers written without thousands separators, recomputed values added. Quoted values from Nation (2006) come from its abstract; they are not covered by this site's CC BY 4.0 license, and the publisher's terms apply. Derived values: figures in derived_value were computed by Feedback & Forgetting from the inputs named in formula. License for this site's selection, arrangement, notes and derived values: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). read_level records how much of each source was read: full text, abstract only, or citation only. Checked 2026-11-06.",
  "lic": "CC BY 4.0",
  "lic_url": "https://creativecommons.org/licenses/by/4.0/",
  "by": "Feedback & Forgetting",
  "url": "https://feedbackandforgetting.com/language-minds/vocabulary-size/",
  "from": [
    "Brysbaert, Stevens, Mandera & Keuleers (2016), Frontiers in Psychology, doi:10.3389/fpsyg.2016.01116, Tables 3 and 4 and text (CC BY 4.0)",
    "Abstract of Nation (2006), The Canadian Modern Language Review, doi:10.3138/cmlr.63.1.59, as deposited by the publisher with Crossref"
  ],
  "how": "Compiled by Feedback & Forgetting from the data listed",
  "data_by": [
    "Brysbaert, M., Stevens, M., Mandera, P., & Keuleers, E. (2016). How many words do we know? Practical estimates of vocabulary size dependent on word definition, the degree of language input and the participant's age. Frontiers in Psychology 7: 1116, doi:10.3389/fpsyg.2016.01116, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), Tables 3 and 4 and text",
    "Nation, I. (2006). How large a vocabulary is needed for reading and listening? The Canadian Modern Language Review 63(1), 59–82, doi:10.3138/cmlr.63.1.59 (abstract; quoted values, publisher's terms apply)"
  ]
}