LanguageGUI is an innovative open-source design system and UI Kit specifically crafted to provide large language models (LLMs) with the ability to format text outputs into rich graphical user interfaces. By allowing developers to create and customize unique UI elements, LanguageGUI simplifies the integration of LLMs into applications, enabling them to produce outputs that are not only functional but also aesthetically pleasing. Users can easily clone the UI Kit from Figma, customize it to suit their application needs, and enhance their interfaces with a variety of pre-built screens, conversational widgets, and styling options, including dark mode. This makes LanguageGUI an invaluable resource for those looking to improve user interaction through visually appealing designs.