Hearing and Speech Sciences, Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD.
Human Development and Quantitative Methodology, University of Maryland, University of Maryland, College Park, MD.
Am J Speech Lang Pathol. 2024 Jul 3;33(4):1986-2001. doi: 10.1044/2024_AJSLP-23-00457. Epub 2024 Jun 5.
Prior work has identified weaknesses in commonly used indices of lexical diversity in spoken language samples, such as type-token ratio (TTR) due to sample size and elicitation variation, we explored whether TTR and other diversity measures, such as number of different words/100 (NDW), vocabulary diversity (VocD), and the moving average TTR would be more sensitive to child age and clinical status (typically developing [TD] or developmental language disorder [DLD]) if samples were obtained from standardized prompts.
We utilized archival data from the norming samples of the Test of Narrative Language and the Edmonton Narrative Norms Instrument. We examined lexical diversity and other linguistic properties of the samples, from a total of 1,048 children, ages 4-11 years; 798 of these were considered TD, whereas 250 were categorized as having a language learning disorder.
TTR was the least sensitive to child age or diagnostic group, with good potential to misidentify children with DLD as TD and TD children as having DLD. Growth slopes of NDW were shallow and not very sensitive to diagnostic grouping. The strongest performing measure was VocD. Mean length of utterance, TNW, and verbs/utterance did show both good growth trajectories and ability to distinguish between clinical and typical samples.
This study, the largest and best controlled to date, re-affirms that TTR should not be used in clinical decision making with children. A second popular measure, NDW, is not measurably stronger in terms of its psychometric properties. Because the most sensitive measure of lexical diversity, VocD, is unlikely to gain popularity because of reliance on computer-assisted analysis, we suggest alternatives for the appraisal of children's expressive vocabulary skill.
先前的研究已经发现，在口语样本中常用的词汇多样性指标（如类型-令牌比（TTR））存在弱点，例如由于样本大小和引出方式的差异，我们探讨了 TTR 以及其他多样性指标（如每 100 个词的不同词数（NDW）、词汇多样性（VocD）和移动平均 TTR）是否会更敏感于儿童年龄和临床状态（典型发育[TD]或发育性语言障碍[DLD]），如果从标准化提示中获取样本。
我们利用了测试叙事语言和埃德蒙顿叙事规范工具的标准化样本的档案数据。我们检查了来自总共 1048 名 4-11 岁儿童的样本的词汇多样性和其他语言特征；其中 798 名被认为是 TD，而 250 名被归类为语言学习障碍。
TTR 对儿童年龄或诊断组的敏感性最低，很可能错误地将 DLD 儿童识别为 TD，将 TD 儿童识别为患有 DLD。NDW 的增长斜率较浅，对诊断分组的敏感性不高。表现最好的测量指标是 VocD。平均话语长度、TNW 和动词/话语都显示出良好的增长轨迹和区分临床和典型样本的能力。
这项研究是迄今为止规模最大、控制最好的研究，再次证实 TTR 不应在儿童临床决策中使用。另一个流行的测量指标 NDW 在心理测量特性方面并没有可衡量的优势。由于词汇多样性最敏感的测量指标 VocD 由于依赖计算机辅助分析，不太可能受到欢迎，因此我们建议了替代方法来评估儿童的表达词汇技能。
