OpenDial is a Java-based, domain-independent toolkit for developing spoken dialogue systems. OpenDial was originally designed to perform dialogue management tasks, but it can also be used to build full-fledged dialogue systems, integrating e.g. speech recognition, language understanding, generation, speech synthesis, multimodal processing and situation awareness.

The purpose of OpenDial is to combine the benefits of logical and statistical approaches to dialogue modelling. The toolkit relies on probabilistic rules to represent the domain models in a compact and human-readable format. Supervised or reinforcement learning techniques can be applied to estimate unknown parameters from small amounts of data (see Lison (2014) for details). The hybrid approach adopted by OpenDial makes it possible to easy incorporate expert knowledge and domain-specific constraints within a robust, probabilistic framework.

OpenDial is designed as a blackboard architecture in which all modules are connected to a central information hub representing the dialogue state (encoded as a Bayesian Network). A collection of plugins is available to connect external components for speech recognition, parsing, speech synthesis, etc.. New modules can also be easily implemented and integrated into the  architecture.

The toolkit has been originally developed by the Language Technology Group of the University of Oslo (Norway), with Pierre Lison as main developer.


[05.04.2016]   New release: version 1.5 of OpenDial! The new version includes new functionalities such as the support for custom functions and the ability to directly manipulate relational structures - such as dependency trees or hierarchical tasks - in the probabilistic rules.
Version 1.4 of OpenDial is out! It includes an interactive domain editor to easily design and evaluate dialogue domains.  The build framework is also switched to Gradle.
[07.05.2015] A new release of OpenDial (version 1.3) is available. The release includes bug fixes, performance improvements and new functionalities  (such as Voice Activity Recognition).
[25.03.2015] Due to Google Code's shutdown, the OpenDial toolkit has migrated to a new website:, while the code repository is moved to GitHub.
 [08.12.2014] The version 1.1 of OpenDial is out! See the release notes to know more about the latest upgrades and extensions. One important change is the switch to Java 8.
[18.04.2014] An updated version (0.95) of OpenDial is now released! One can now connect various plugins into the architecture. There is also basic support for incremental processing.
 [04.02.2014] See here to watch OpenDial deployed in a situated dialogue system for human-robot interaction (using the Nao robot as robotic platform).
 [31.01.2014] Version 0.9 of OpenDial is finally available! The version contains a refactored and documented code base, an improved graphical interface, concrete examples of dialogue domains, and a collection of unit tests.