Title
Towards automatic assessment of spontaneous spoken English.
Abstract
With increasing global demand for learning English as a second language, there has been considerable interest in methods of automatic assessment of spoken language proficiency for use in interactive electronic learning tools as well as for grading candidates for formal qualifications. This paper presents an automatic system to address the assessment of spontaneous spoken language. Prompts or questions requiring spontaneous speech responses elicit more natural speech which better reflects a learner’s proficiency level than read speech. In addition to the challenges of highly variable non-native, learner, speech and noisy real-world recording conditions, this requires any automatic system to handle disfluent, non-grammatical, spontaneous speech with the underlying text unknown. To handle these, a strong deep learning based speech recognition system is applied in combination with a Gaussian Process (GP) grader. A range of features derived from the audio using the recognition hypothesis are investigated for their efficacy in the automatic grader. The proposed system is shown to predict grades at a similar level to the original examiner graders on real candidate entries. Interpolation with the examiner grades further boosts performance. The ability to reject poorly estimated grades is also important and measures are proposed to evaluate the performance of rejection schemes. The GP variance is used to decide which automatic grades should be rejected. Back-off to an expert grader for the least confident grades gives gains.
Year
DOI
Venue
2018
10.1016/j.specom.2018.09.002
Speech Communication
Keywords
Field
DocType
Automatic assessment of spoken english,Spontaneous speech,Pronunciation,Gaussian process,Rejection scheme
Grading (education),Computer science,Second language,Interpolation,Speech recognition,Gaussian process,Artificial intelligence,Deep learning,Spoken language
Journal
Volume
ISSN
Citations 
104
0167-6393
0
PageRank 
References 
Authors
0.34
37
7
Name
Order
Citations
PageRank
Yu Wang1598.66
Mark J. F. Gales23905367.45
Kate Knill324928.02
Konstantinos G. Kyriakopoulos42411.04
Andrey Malinin5397.54
Rogier C. Van Dalen6365.31
Muhammad Rashid733.19