Fluency Scoring of English Speaking Tests for Nonnative Speakers Using a Native English Phone Recognizer

Abstract

In the previous works on fluency, Fillmore defined the 4 elements of fluency: the ability to talk at length with minimal pauses, the ability to talk cohesively and logically, the ability to talk in a wide range of contexts or situations, and the ability to create talk [4]. Crystal defined the fluency as 'smooth, rapid, effortless use of language' [5]. Chamber established the definition of fluency in qualitative and quantitative aspects and proposed the evaluation guide for foreign language speaking tests. Chamber's experiments showed that the important elements for fluency evaluation are the rate of speech, the frequency or position of pause, and hesitations, which are temporal and quantitative features [2]. Kormos investigated the effects of temporal and lexical features on fluency evaluation and asserted that important features are the speech rate, the phonation time ratio, the number of stressed words, and the accuracy [3]. In the Deshmukh et al.'s study, 8 prosodic and 8 lexical features were extracted for fluency evaluation, and good performance was generally achieved with the lexical features among which the