The CSLU shell (CSLUsh), is a collection of modular building blocks which aim to provide the user with a powerful, extendible, research, development and implementation environment. Implemented in C with standardized Tcl/Tk interfaces to provide a scripting and visualization environment, it allows a exible cast for both research algorithms and system deployment. This shell is the architecture on which the CSLU Toolkit is built and may be downloaded for non-commercial use from http://www.cse.ogi.edu/CSLU/toolkit.