Mark (@mark_liberman) is a Christopher H. Browne Distinguished Professor of Linguistics and Professor of Computer Science at the University of Pennsylvania. Mark is also the Director of Linguistic Data Consortium. His research interests include corpus-based phonetics, the phonology and phonetics of lexical tone, and its relationship to intonation; gestural, prosodic, morphological and syntactic ways of marking focus, and their use in discourse; and formal models for linguistic annotation. Mark blogs at Language Log.