Vocabulary distribution: a measure to words' complexity
Ying Xiao-don · 2014
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.