OVAL Mission

Stanford Open Virtual Assistant Lab (OVAL) is dedicated to advancing virtual assistant technology and creating an industrial ecosystem that protects consumer privacy and promotes open competition.

  • Fundamental research in virtual assistant technology
  • Accelerate development through open collaboration
  • Increase adoption by making quality software openly available
  • Enable sharing with privacy

OVAL is supported by the National Science Foundation under Grant No. 1900638, and by the Alfred P. Sloan Foundation under Grant No. G-2020-13938.

Research Goals

  • To create an open, non-proprietary linguistic web.
  • To accelerate and democratize natural language interface technology via open collaboration.
  • To protect privacy with interoperable virtual assistants that can run on users' devices.


Natural language programming

A new virtual assistant architecture where a neural semantic parser directly translates natural language into a custom high-level programming language (ThingTalk) for assistants. Users can use natural language to automate workflows by composing functions from different domains.


A WORA (Write-Once-and-Run-Anywhere) platform of skills that can be run on any virtual assistants; these skill can be automatically made available to Alexa and Google Assistant if desired. Thingpedia skills are interoperable to support natural language programming. By minimizing redundant effort, lowering the barrier of entry for new assistants, and hence removing dependency on a small number of proprietary assistants, Thingpedia can flourish to contain as many skills as there are web pages.


An open-source neural semantic parser that translates natural language into formal languages. All the training data are also publicly available. Companies can incorporate LUInet in their own virtual assistants, websites, apps, and and voice services.


A tool that lets non-ML-experts extend Thingpedia and Thingtalk, and craft training data to extend LUInet with sentences in their domains. By empowering companies to create and own interfaces for their domains, LUInet can become more knowledgeable than any proprietary models. This democratizes AI and accelerates AI development.


The first open-source, social virtual assistant that can be run on local devices to protect privacy. Users can tell their assistant who, what, when, where, and how can their data can be shared, all without disclosing their data to a third party.

A virtual assistant communication protocol

A general, secure protocol based on remote ThingTalk programs to enable interoperability of virtual assistants. This supports federation of assistants, similar to email, rather than centralized monopolies.


Brassau combines voice with automatically generated graphical user interfaces to take advantage of the best of each modality.

Blockchain-based technology for audits of third-party sharing

We use communicating virtual assistants to enforce user-specified sharing contracts across institutes; these contracts are made revocable and auditable through efficient blockchain technology based on federated Byzantine agreements.

Presentations & Interviews







Senior Members

PhD Students

Alumni and Former Students

Previous members of our team include (in cronological order)

We thank them for their valuable contribution.