A natural language user interface for computer-aided design systems (CAD) comprises a natural language command module including a parser, language database and a CAD model analyzer, and a natural language server module including a second, increased capability parser, a second, preferably larger language database and a CAD context database. The CAD model analyzer analyzes and retrieves associated CAD model information related to a parsed voice command and the CAD context database provides specific CAD related contextual information to facilitate parsing and interpreting CAD specific commands. The natural language server program module may also include an artificial intelligence based query generator and communicate through a network or cloud with resource providers such as third-party market places or suppliers to generate queries for retrieval of third party supplied information necessary to respond to or execute CAD specific voice commands. The natural language user interface may query a user for missing information.