Khalil Sima’an conducts research in the area of computational linguistics and language technology. He develops theories and computer models of the human capacity to understand written texts and translate them into other texts or actions during processes such translation, paraphrasing and summarising. His current team is studying machine translation models capable of preserving meaning. Sima’an's models are designed to generalise latent structures in large volumes of translation data into statistical grammars of meaning equations. Computer models capable of preserving meaning are key to both scientific research on human language processing and language technology applications.

Prior to his appointment as an assistant professor at the UvA's Institute for Logic, Language and Computation (ILLC) in 2003, Sima’an was a fellow at the Royal Netherlands Academy of Arts and Sciences (KNAW). He has served as an associate professor at the ILLC since 2011, where he heads a group currently researching statistical models for machine translation and morpho-syntactic analysis. Sima’an held positions as a guest researcher at Technion University of Technology (Israel), the University of Maryland (US), Johns Hopkins University (US) and Dublin City University (Ireland). Sima’an has received numerous grants, including a Vidi grant (2006) and a Vici grant (2013) from the Netherlands Organisation for Scientific Research (NWO). He is a member of the editorial board of the journal Machine Translation and the Journal of Natural Language Engineering.