Measuring lexical diversity in texts that have different lengths is problematic because length has a significant effect on the number of types a text contains, thus hampering any comparison. Treffers-Daller et al. (2018) recommended a simple solution, namely counting the number of types in a section of a given length that was extracted from the middle of each of the texts to be analysed. By applying this approach to second language essays, the authors observed that using the number of types was slightly more effective for differentiating amongst the Common European Framework of Reference for Languages (CEFR) levels than were the Type-Token Ratio (TTR) and the Guiraud index and that these three indices were more effective than were mathematically more complex ones. However, their conclusions regarding these two points are incorrect, and a less basic approach should be used. The last section addresses two broader issues in applied linguistics that are highlighted by these problems.

中文翻译：

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回归测量词汇多样性的基础：太简单而不真实


测量具有不同长度的文本中的词汇多样性是有问题的，因为长度对文本包含的类型数量有显着影响，从而妨碍了任何比较。特雷弗斯-达勒等人。 （2018）推荐了一个简单的解决方案，即计算从要分析的每个文本中间提取的给定长度部分中的类型数量。通过将这种方法应用于第二语言论文，作者观察到，使用类型数量比类型标记比率 (TTR) 和 Guiraud 更能有效地区分欧洲共同语言参考框架 (CEFR) 级别。指数，并且这三个指数比数学上更复杂的指数更有效。然而，他们关于这两点的结论是不正确的，应该使用不太基本的方法。最后一节讨论了这些问题所强调的应用语言学中的两个更广泛的问题。