a general-purpose speech recognition toolkit.


"Alex Waibel's NN speech group"


The Janus Recognition Toolkit (JRTk) is a general-purpose speech recognition toolkit useful for both research and application development and is part of the JANUS speech-to-speech translation system.

The JRTk provides a flexible Tcl/Tk script based environment which enables researchers to build state-of-the-art speech recognizers and allows them to develop, implement, and evaluate new methods. It implements an object oriented approach that unlike other toolkits is not a set of libraries and precompiled modules but a programmable shell with transparent, yet efficient objects.

Since version 5 JRTk features the IBIS decoder, a one-pass decoder that is based on a re-entrant single pronunciation prefix tree and makes use of the concept of linguistic context polymorphism. It is therefore able to incorporate full linguistic knowledge at an early stage. It is possible to decode in one pass, using the same engine in combination with a statistical n-gram language model as well as context- free grammars. It is also possible to use the decoder to rescore lattices in a very efficient way.


source code



IP Agreement

Commercial and research licenses are available. Terms and conditions as well as further information can be inquired by contacting Prof. Alex Waibel at ahw∂cs cmu edu.


Linux, Mac, or Windows; Tcl 8.5 or later; BLAS library

Required Acknowledgment

Hagen Soltau, Florian Metze, Christian Fügen, Alex Waibel, "A One Pass-Decoder Based On Polymorphic Linguistic Context Assignment", Automatic Speech Recognition and Understanding Workshop 2001, ASRU 2001, Trento, Italy, 25. October 2001.

Torsten Zeppenfeld, Michael Finke, Klaus Ries, Martin Westphal, Alex Waibel, "Recognition Of Conversational Telephone Speech Using The Janus Speech Engine", International Conference on Acoustics, Speech, and Signal Processing 1997, ICASSP 1997, Munich, Germany, 01. April 1997 .


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