A newly bought Furby starts out speaking entirely Furbish , the unique language with short words , simple syllables , and various other sounds , that all Furbies use , but are programmed to speak less Furbish as they learn more English as they `` grow '' . A newly purchased Furby starts out speaking entirely Furbish , the unique language with short words , simple syllables , and various other sounds , but are programmed to speak less Furbish as they learn more English as they `` grow '' .