Growing up with multiple siblings might negatively affect language development. This study examined the associations between birth order, sibling characteristics and parent‐reported vocabulary size in 6163 Norwegian 8‐ to 36‐month‐old children (51.4% female). Results confirmed that birth order was negatively associated with vocabulary, yet exhibited a U‐shaped pattern. A data‐driven measure of “child‐to‐caregiver ratio” in the household was developed, in which old‐enough siblings—females 1–3 years earlier than males—were considered caregivers for their younger siblings. This measure explained variance in vocabulary better than birth order, and indicates sex‐differences in the age at which older siblings contribute to, rather than deplete, available resources. A child‐to‐caregiver ratio might better capture the interplay between language‐learning resources and demands within households.

中文翻译：

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早期词汇习得：从出生顺序效应到儿童与照顾者的比例


与多个兄弟姐妹一起长大可能会对语言发展产生负面影响。本研究检查了 6163 名挪威 8 至 36 个月大儿童 （51.4% 为女性） 的出生顺序、兄弟姐妹特征和父母报告的词汇量之间的关联。结果证实，出生顺序与词汇呈负相关，但表现出 U 形模式。开发了一种数据驱动的家庭“儿童与照顾者比率”测量方法，其中足够大的兄弟姐妹（比男性早 1-3 年的女性）被视为弟弟妹妹的照顾者。该测量比出生顺序更好地解释了词汇的差异，并表明哥哥姐姐对可用资源的贡献而不是耗尽可用资源的年龄差异。儿童与照顾者的比例可能更好地捕捉到家庭内部语言学习资源和需求之间的相互作用。