Optimism is growing that the near future will witness rapid growth in human-computer interaction using voice. System prototypes have recently been built that demonstrate speaker-independent real-time speech recognition, and understanding of naturally spoken utterances with vocabularies of 1000 to 2000 words, and larger. Already, computer manufacturers are building speech recognition subsystems into their new product lines. However, before this technology can be broadly useful, a substantial knowledge base is needed about human spoken language and performance during computer-based spoken interaction. This paper reviews application areas in which spoken interaction can play a significant role, assesses potential benefits of spoken interaction with machines, and compares voice with other modalities of human-computer interaction. It also discusses information that will be needed to build a firm empirical foundation for the design of future spoken and multimodal interfaces. Finally, it argu...

This work is part of a project aimed at developing a speech recognition system for language instruction that can assess the quality of pronunciation, identify pronunciation problems, and provide the student with accurate feedback about specific mistakes. Previous work was mainly concerned with scoring the quality of pronunciation. In this work we focus on automatic detection of mispronunciation. While scoring quantifies the mispronunciation, detection identifies the occurrence of a specific problem. Detecting pronunciation problems is necessary for providing feedback to the student. We use pronunciation scoring techniques to evaluate the performance of our mispronunciation model. 1.

Every year in the Netherlands lots of foreigners take part in examinations aimed at testing their proficiency in Dutch. In order to achieve greater efficiency and lower costs, attempts are being made to automate at least part of the testing procedure. Automatic testing of receptive skills such as reading and listening appears to be relatively simple, because the response tasks that are often used-multiple choice, matching

The ultimate aim of the research reported on in this paper is to develop a system for automatic assessment of foreign speakers' pronunciation of Dutch. The aim of the experiment described here was to determine whether pronunciation ratings assigned by human experts could be predicted on the basis of scores calculated by an automatic speech recognizer. To this end 20 native and 60 non-native speakers of Dutch read ten phonetically rich sentences over the telephone. The automatic speech recognizer was trained with read speech of 4019 Dutch subjects with varying regional accents. The results show that the human scores can be accurately predicted, even in the case of telephone speech. Analysis of the various types of human ratings and automatic measures provides more insight into the relationship between human and machine scores and indicates how the automatic measures can be further improved to achieve even greater predictive power. 1 Introduction Developing computer tests for productive...

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Low-proficiency non-native speakers represent a significant challenge for large-vocabulary continuous speech recognition (LVCSR). Acoustic models are confused by a heavy accent

Prosody—suprasegmental characteristics of speech such as pitch, rhythm, and loudness— is a rich source of information in spoken language and can tell a listener much about the internal state of a speaker. This thesis explores the role of prosody in conveying three very different types of speaker state: paralinguistic state, in particular emotion; pragmatic state, in particular questioning; and the state of spoken language proficiency of non-native English speakers. Paralinguistics. Intonational features describing pitch contour shape were found to dis-criminate emotion in terms of positive and negative affect. A procedure is described for clustering groups of listeners according to perceptual emotion ratings that foster further understanding of the relationship between acoustic-prosodic cues and emotion perception. Pragmatics. Student questions in a corpus of one-on-one tutorial dialogs were found to be signaled primarily by phrase-final rising intonation, an important cue used in conjunc-tion with lexico-pragmatic cues to differentiate the high rate of observed declarative questions from proper declaratives. The automatic classification of question form and

Experiments were carried out to determine whether log-likelihood ratios (LRs) can be employed to improve automatic assessment of Dutch pronunciation. Read speech of natives and non-natives was judged by three groups of expert raters and was then analyzed by means of a continuous speech recognizer. Three automatic measures were calculated, two LRs and rate of speech (ros), and then compared with the expert ratings. It appears that expert ratings of pronunciation quality can accurately be predicted on the basis of ros alone and that LRs do not contribute to better prediction. However, LRs can be useful to automatic pronunciation assessment because they can help detect fast speakers who produce totally wrong sentences. 1.

this paper we first describe the goals of the present experiment (section 2). We then go on to consider how this study differs from previous ones (section 3). In section 4 the methodology is described. The results of this experiment are presented in section 5. Finally, in section 6 the results are discussed and some conclusions are drawn.

Proficiency testing is an important ingredient in successful language teaching. However, repeated testing for course placement, over the course of instruction or for certification can be time-consuming and costly. We present the design and validation of the Versant Arabic Test, a fully automated test of spoken Modern Standard Arabic, that evaluates test-takers ' facility in listening and speaking. Experimental data shows the test to be highly reliable (testretest r=0.97) and to strongly predict performance on the ILR OPI (r=0.87), a standard interview test that assesses oral proficiency. 1