Constantine Lignos
University of Southern California Information Sciences Institute

Email: firstname at lastname dot org

I research and develop effective and efficient natural language processing models. My work is fundamentally interdisciplinary, combining machine learning, linguistics, and language acquisition/processing. I've applied my work in many domains, such as natural language understanding, robotics, autism research, and language acquisition.

I'm located at the USC Information Sciences Institute Boston office. If you're interested in joining us at ISI Boston, take a look at the jobs posted on the USC Careers site at the Waltham, MA location.

I did my graduate work in Computer Science at The University of Pennsylvania (Ph.D. 2013), advised by Mitch Marcus and Charles Yang. I then completed a post-doctoral fellowship at The Children's Hospital of Philadelphia exploring clinical applications of statisical models of language processing. I was a researcher at BBN Technologies from 2015-2017.

Latest news

Forthcoming article in Machine Translation

My article Combining rule-based and statistical mechanisms for low-resource named entity recognition will appear in a forthcoming special issue of Machine Translation.

Special issue of Linguistic Variation

The special issue The locus of linguistic variation that I co-edited will be published as issue 16:2 of Linguistic Variation.

Chapter in Cambridge Handbook of Morphology

My chapter with Charles Yang, Morphology and language acquisition, will appear in The Cambridge Handbook of Morphology.


MORSEL: a cognitively-motivated state-of-the-art unsupervised morphological analyzer I developed for Morpho Challenge 2010. It achieved state-of-the-art results in English and Finnish.

Codeswitchador: a system for identifying code-switching in social media data. This work enables the creation of large scale corpora of code-switching and identification of bilingual users. I developed this as a participant of the SCALE summer workshop at the Johns Hopkins Center of Excellence in Human Language Technology.

Regrettably, most of my research over the last few years is closed-source. However, many older projects are publicly available on GitHub.


I teach researchers to write great Python code. The notes for the bootcamps I've done are available at Python Boot Camp for Researchers.

I maintain a list of common mistakes that programmers new to Python make: Anti-Patterns in Python Coding.

In Spring 2011 and 2012, I taught one of the CIS department's "mini-courses," Python Programming (CIS 192).

In the past I've also led some informal groups for learning Python. The slides from those groups can be found on my Python for Language Researchers Site.