His area of expertise revolves around statistical processing human language, and in particular speech recognition. He participated in DARPA/NIST competitions, notably contributing to the winning machine translation competition in English to Chinese in 2008. He co-authored about 20 granted patents and numerous publications. He serves a reviewer for all major speech and natural language research publications. He served in the organizing committee of ASRU 2011, 2013, and 2015. In 2010, he co-lead with Geoffrey Zweig the CLSP-JHU workshop on Segmental Conditional Random Fields for Speech Recognition. He served in the IEEE Speech and Language Technical Committee.