This thesis describes a Natural Language (NL) interface to a VHDL modeling tool called the Modeler's Assistant. The primary motivation for the interface developed in this research work is to permit VLSI modelers who are not proficient in VHDL to rapidly produce correct VHDL models from manufacturer's descriptions. This tool should also be useful in teaching the VHDL language. The Modeler's Assistant has supported graphical capture of behavioral models in the form of Process Model Graphs consisting of processes (nodes) interconnected by signals (arcs). The NL interface that has been constructed allows modelers to specify the behavior for the process nodes using a restricted form of English called ModelSpeak. A Spell-checking routine (of the UNIX operating system) is invoked to reduce input errors. Also, the grammar employed, accepts multi-sentence descriptions rather than just a single sentence. Correct VHDL for each process is synthesized automatically, but user interaction is solicited where needed to resolve ambiguities such as the scope of loops and the type of signals and variables. The Modeler's Assistant can then assemble the VHDL code for these processes, along with the information about the interface description from the PMG, into a complete entity model. / Master of Science