This study examines when the vocabulary knowledge of Japanese heritage speakers (HSs; N = 427, Mage = 9.96, female = 213) begins to diverge from monolingual counterparts (N = 136, Mage = 6.69, female = 65) and what factors explain individual differences in HS development. Vocabulary of HSs began to diverge from 5.61 years and this difference lasted until they were young adults. We also administered a fit‐for‐purpose questionnaire in 2021–2023 and identified six experiential latent factors: Holiday, School, Community, Proficiency, Literacy, and Home. Structural modeling indicates that Holiday predicted vocabulary scores, while Holiday and Literacy predicted Proficiency. Our findings highlight the importance of immersion experiences and literacy engagement for heritage language development.

中文翻译：

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模拟词汇发展中的个体差异：对日本传统使用者的大规模研究


本研究探讨了日语传统使用者（HS；N = 427，Mage = 9.96，女性 = 213）的词汇知识何时开始与单语语言对应者（N = 136，Mage = 6.69，女性 = 65）出现差异，以及哪些因素解释了个体差异HS发展的差异。 HS的词汇量从5.61岁开始出现分化，这种差异一直持续到他们年轻的时候。我们还在 2021-2023 年进行了一份适合目的的调查问卷，并确定了六个体验性潜在因素：假期、学校、社区、熟练程度、读写能力和家庭。结构模型表明，Holiday 预测了词汇分数，而 Holiday 和 Literacy 则预测了熟练程度。我们的研究结果强调了沉浸式体验和识字参与对于传统语言发展的重要性。