{
  "name": "Starting age, grammar and accent: values and tags from two study abstracts",
  "desc": "Starting age and second-language learning, one row per claim or value. Quoted values: figures in the quoted_value column are quoted from the publications in source_doi, at the table or page in source_location. They are not covered by this site's CC BY 4.0 license; the publishers' terms apply. The 2018 online-quiz study discussed on the page is not included in this file; its figures and tags appear only in the article text. Derived values: this file has none. 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/critical-period-hypothesis/",
  "from": [
    "Abstracts of Johnson & Newport (1989), Cognitive Psychology, doi:10.1016/0010-0285(89)90003-0, and Flege, Munro & MacKay (1995), The Journal of the Acoustical Society of America, doi:10.1121/1.413041 (quoted figures)",
    "Title only for Birdsong & Molis (2001), Journal of Memory and Language, doi:10.1006/jmla.2000.2750"
  ],
  "how": "Compiled by Feedback & Forgetting from the data listed",
  "data_by": [
    "Johnson, J. S., & Newport, E. L. (1989). Cognitive Psychology 21(1): 60–99, doi:10.1016/0010-0285(89)90003-0, abstract (quoted figures only)",
    "Flege, J. E., Munro, M. J., & MacKay, I. R. A. (1995). The Journal of the Acoustical Society of America 97(5): 3125–3134, doi:10.1121/1.413041, abstract (quoted figures only)",
    "Birdsong, D., & Molis, M. (2001). Journal of Memory and Language 44(2): 235–249, doi:10.1006/jmla.2000.2750 (title only)"
  ]
}