Stephen Mayhew
Senior Machine Learning Engineer at Duolingo
Pittsburgh, Pennsylvania, United States
Summary
👤
Senior🎓
Top SchoolStephen Mayhew is a Senior Machine Learning Engineer in Pittsburgh with 13 years of experience applying NLP and ML research into production, currently at Duolingo. He holds deep academic roots—PhD work with Dan Roth and research internships at Microsoft and MIT Lincoln Lab—bringing strong probabilistic and language-tech foundations to product problems. Stephen contributes to established open-source NLP tooling (e.g., CogComp's cogcomp-nlp) and has hands-on back-end experience porting and refactoring Java code for real-world use. Known for a curious, pragmatic approach to keyword-driven hiring dynamics, he balances rigorous research instincts with practical engineering for scalable language systems.
13 years of coding experience
10 years of employment as a software developer
Doctor of Philosophy (PhD) Computer Science, Doctor of Philosophy (PhD) Computer Science at University of Illinois Urbana-ChampaignBS Computer Science, BS Computer Science at Rose-Hulman Institute of TechnologyDoctor of Philosophy - PhD Computer Science, Doctor of Philosophy - PhD Computer Science at University of Pennsylvania
English, German
Github Skills (3)
java10
javas10
refactoring9
Programming languages (8)
Github contributions (5)
CogComp/cogcomp-nlp
Sep 2015 - Oct 2018
CogComp's Natural Language Processing Libraries and Demos: Modules include lemmatizer, ner, pos, prep-srl, quantifier, question type, relation-extraction, similarity, temporal normalizer, tokenizer, transliteration, verb-sense, and more.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:161 commits, 19 PRs, 7 pushes in 3 years 1 month
Contributions summary:Stephen made several small changes and additions to source code files written in Java, primarily related to porting the code to Java. This includes updating and refactoring Java files, as well as refactoring Javadoc. Their work focused on adapting the code for use with new Java libraries and frameworks and restructuring the codebase for functionality and portability.
ellipsisverbextractionnatural-language-understandingpos-tagging
CogComp/talen
May 2016 - Jul 2019
A way to do annotations for NER. TALEN: Tool for Annotation of Low-resource ENtities
Contributions:1 release, 264 commits, 7 PRs in 3 years 2 months
nlpnamed-entity-recognitionnerannotationslow-resource
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