This paper describes the development of a flexible multi-lingual prediction system for use with an augmentative communication system. A Grammar Description Language (GDL) is used to build a knowledge base about the given language and a Lexicon is used to provide the words. Changing the language of the system is simply a case of swapping the GDL code and the Lexicon to the required type. A Blissymbol prediction system can also be included, which will predict symbols given previous entries using a grammar based on the Blissymbolic language. When used the system will provide grammatically correct predictions which should have a higher hit rate than systems using traditional word counting techniques.