Duolingo Inc., a language-learning platform that has amassed more than 1 million paid subscribers and has a $1.5 billion valuation, has found its first general counsel.

The Pittsburgh-based venture capital-backed startup named Stephen Chen as its top lawyer on Tuesday. An in-house tech veteran with extensive dealmaking experience, Chen has worked in the legal departments of Yahoo, VMWare Inc., Marin Software and, most recently, Proofpoint Inc., a cybersecurity software company in Silicon Valley.