Context-sensitive neighborhood controlled embedding (CS-NCE) graph grammar can be used to formalize the syntactical rules of a wide range of visual languages. In this paper, we describe a visual language design system (VLDS) that we have implemented to assist users in designing visual languages based on the CS-NCE graph grammar The VLDS greatly facilitates tasks both of designing new visual languages, and formalizing the syntactical rules of existing visual languages through the GUI.