Middle and secondary science textbooks have long been a primary support for instruction, often leading to heavy emphasis on domain-specific vocabulary. A longitudinal study was conducted to compare vocabulary loads of science textbooks published since 2010 to results of two previous studies going back to 1983. In each study, textbooks chosen represent convenience samples of commonly used middle and secondary science textbooks. Vocabulary emphasis in science textbooks remains high, and may present a problem for struggling readers and English language learners (ELL). Some vocabulary loads were found to approach or even exceed recommended limits for vocabulary instruction in modern foreign language courses. Also, science vocabulary can present an additional challenge for native English speakers and ELLs since many terms have no common colloquial English or native language equivalents. Recommendations for how to promote effective science vocabulary development are provided. Overall, over three decades there has been little change in heavy emphasis on vocabulary in middle and secondary science textbooks.

中文翻译：

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中、中学科学课本词汇量的纵向研究

中学和中学科学教科书长期以来一直是教学的主要支持，往往导致对特定领域词汇的高度重视。进行了一项纵向研究，将 2010 年以来出版的科学教科书的词汇量与可追溯到 1983 年的前两项研究的结果进行比较。在每项研究中，所选教科书都代表了常用的中、中学科学教科书的便利样本。科学教科书中的词汇重点仍然很高，这可能会给有困难的读者和英语学习者 (ELL) 带来问题。发现一些词汇量接近甚至超过现代外语课程中词汇教学的推荐限制。还，科学词汇对于以英语为母语的人和 ELL 来说可能是一个额外的挑战，因为许多术语没有通用的口语英语或母语对应词。提供了如何促进有效的科学词汇发展的建议。总体而言，三十年来，中、中学科学教科书中对词汇的高度重视几乎没有变化。