Title
Spoken Language Understanding of Human-Machine Conversations for Language Learning Applications
Abstract
Spoken language understanding (SLU) in human machine conversational systems is the process of interpreting the semantic meaning conveyed by a user's spoken utterance. Traditional SLU approaches transform the word string transcribed by an automatic speech recognition (ASR) system into a semantic label that determines the machine's subsequent response. However, the robustness of SLU results can suffer in the context of a human-machine conversation-based language learning system due to the presence of ambient noise, heavily accented pronunciation, ungrammatical utterances, etc. To address these issues, this paper proposes an end-to-end (E2E) modeling approach for SLU and evaluates the semantic labeling performance of a bidirectional LSTM-RNN with input at three different levels: acoustic (filterbank features), phonetic (subphone posteriorgrams), and lexical (ASR hypotheses). Experimental results for spoken responses collected in a dialog application designed for English learners to practice job interviewing skills show that multi-level BLSTM-RNNs can utilize complementary information from the three different levels to improve the semantic labeling performance. An analysis of results on OOV utterances, which can be common in a conversation-based dialog system, also indicates that using subphone posteriorgrams outperforms ASR hypotheses and incorporating the lower-level features for semantic labeling can be advantageous to improving the final SLU performance.
Year
DOI
Venue
2020
10.1007/s11265-019-01484-3
JOURNAL OF SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY
Keywords
DocType
Volume
Spoken language understanding,Human-machine conversational systems,Computer assisted language learning,End-to-end modeling,Education
Journal
92.0
Issue
ISSN
Citations 
SP8
1939-8018
0
PageRank 
References 
Authors
0.34
0
6
Name
Order
Citations
PageRank
Qian Yao152751.55
Rutuja Ubale223.17
Patrick Lange398.42
Keelan Evanini47920.23
Vikram Ramanarayanan57013.97
Frank K. Soong61395268.29