Lexical proficiency in a second language (L2) has long been effectively assessed through the measurement of various lexical indices, or textual characteristics that act as observable indicators of such conceptual categories as lexical richness, diversity, sophistication, and fluency. While many studies have established links between these lexical characteristics and levels of overall language proficiency, languages other than L2 English rarely feature in such research. The current study addresses this gap by investigating a less commonly studied language, Russian, while paying specific attention to the operationalization of proficiency through an American Council for the Teaching of Foreign Languages Proficiency Guidelines‐based procedure. The study analyzes eight lexical proficiency indices in a corpus of essays written by learners of Russian at different proficiency levels. Our analyses demonstrate that seven indices (i.e., word length in letters, word length in syllables, word length in morphemes, unique tokens per text, unique lemmas per text, and measure of textual lexical diversity for tokens and for lemmas) changed significantly with the increase in proficiency. Only one index—the proportion of content versus function words—did not reliably track the increase in proficiency. The findings confirm the usefulness of lexical proficiency measures in tracking lexical development in L2 Russian and increase the repertoire of these indices for L2 Russian.

中文翻译：

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使用词汇复杂度、多样性和流利度指数评估俄语作为第二语言的词汇熟练程度

长期以来，第二语言 （L2） 的词汇熟练程度一直通过测量各种词汇指数或文本特征来有效评估，这些指标充当词汇丰富性、多样性、复杂性和流利度等概念类别的可观察指标。虽然许多研究已经确定了这些词汇特征与整体语言熟练度水平之间的联系，但 L2 英语以外的语言很少出现在此类研究中。目前的研究通过调查一种不太常用的语言俄语来解决这一差距，同时通过基于美国外语教学委员会能力指南的程序特别关注熟练程度的作化。该研究分析了不同熟练程度的俄语学习者撰写的论文语料库中的八个词汇熟练度指数。我们的分析表明，七个指数（即字母中的词长、音节中的词长、语素中的词长、每个文本的唯一词元以及词元和词元的文本词汇多样性的测量）随着熟练程度的提高而显着变化。只有一个指数——内容与虚词的比例——没有可靠地跟踪熟练程度的提高。研究结果证实了词汇熟练度测量在跟踪 L2 Russian 词汇发展方面的有用性，并增加了 L2 Russian 的这些指标的库。