Syntactica is a software application tool designed to let you study natural language structure in a fun, interactive way. It is designed to be used in conjunction with the text Grammar as Science. The program provides a simple interface for:
Creating grammars (consisting of phrase-structure rules and lexicons)
Viewing the structures they assign to natural language expressions
Transforming those structures by syntactic operations such as movement, deletion and copying.
Syntactica permits many aspects of syntactic theory to be explored. The rule and lexicon windows allow you to assign and control the percolation of syntactic features. The TreeViewer window lets you to perform a variety of formal operations on trees by simply pointing, clicking and using the Transforms panel. Syntactica also allows you to control various constraints on operations, including an elementary version of Subjacency. Originally developed under NeXTSTEP, Syntactica has been ported to JAVA, where it runs under Mac OSX and WIN.