Research

Automatic Speech Recognition and Computational Modeling of Speech

Much of my work has been on acoustic-phonetic modeling in automatic speech recognition. I am interested in how to find suitable representations of acoustic-phonetic categories, how to model phenomena such as pronunciation variation and coarticulation, and how to best exploit training data. In the past I have primarily explored articulatory feature representations for both ASR and automatic language identification. More recently, I have developed an interest in semi-supervised graph-based machine learning methods for aoustic modeling (more info here ).

Statistical Language Modeling

Motivated by the problem of language modeling for morphologically rich languages, I have been working on the development of Factored Language Models (FLMs), which represent words as sets of feature vectors and derive more robust probability estimates by way of a Generalized Backoff procedure that makes use of the feature structure. A relatively short description can be found here ; a more extensive tutorial can be found here . FLMs have been integrated into the SRI language modeling toolkit and have been applied to language modeling for a variety of languages. Our own work has mostly focused on Arabic.

Machine Translation

My students and I have been active in the development of machine translation systems for spoken and written language. In our research we have explored morphological and factored language models for statistical machine translation. More recently I have become interested in modeling the global situational and discourse context of a document or an interaction to improve translation performance (see our past project on Contextual Machine Translation ) and in machine translation for applications in the health domain (see our current TransPHorm project).

Multilingual Speech and Language Processing

I am interested in all forms of statistical speech and language processing for non-English languages. My past work in this area includes automatic speech recognition for Arabic, language identification on a variety of languages, language modeling for Turkish and Arabic, machine translation for Spanish, Italian, German, Finnish, French, Arabic, and Chinese, lexicon development for dialectal Arabic, etc., and many other projects.

Speech and Language Processing for Biomedical and Health Applications

Recently I have developed an interest in applying statistical speech and language processing to improve access to health information and to biomedical research problems. My main project in this area is the TransPHorm project. I have also worked on applying natural language processing representations to the problem of peptide identification.

Human and Machine Learning in Speech Processing

Another pet interest of mine is how human learners (i.e. infants) acquire speech, how machines can be made to learn models of speech, and in the parallels and differences between the two processes.

Click on the links below to find our more about my past and current research projects.