论词汇分布作为词汇复杂度的一个测度

提出了一种评估非母语英语学习者的词汇应用能力的方法,用于提高英语为非母语者的自然语音响应自动评分系统的精度.方法根据词表中每个词在参照语料库的出现频率来估算词汇复杂度,并评定响应中词汇的平均难度等级.基于口语响应中的单词,得出3种特征:相关覆盖率、平均词排名及平均词频,研究了它们对人工语言能力得分的影响程度.最后,探讨了词汇分布特征对自动语音评分系统的影响,重点在于参照语料库的文类和词项类型2个因素的影响.

Vocabulary distribution:a measure to words' complexity

We presents a method that assesses ESL learners' vocabulary usage to improve an automated scoring system of spontaneous speech responses by non-native English speakers. Focusing on vocabulary sophistication,we estimate the difficulty of each word in the vocabulary based on its frequency in a reference corpus and assess the mean difficulty level of the vocabulary usage across the responses( vocabulary profile). Three different classes of features were generated based on the words in a spoken response: coverage-related,average word rank and the average word frequency and the extent to which they influence human-assigned language proficiency scores was studied. Finally,we discussed the influence on the vocabulary features of the automated speech scoring system.