Abstract: A system operable on a small mobile device such as a smart phone uses descriptive languages with a similar style to markup languages used in a thin client but having features characteristic of a fat client. In one form, the system could be a MIDlet on J2ME platform or an executable program on Microsoft Smartphone platform that allows developers to mobilize business applications without the knowledge of complicated J2ME/MIDlet or Microsoft development environments. The system includes an XML language and a Script Language. Applications written in the Script Language can be translated to XML and then optionally compiled to embedded code which can be parsed and interpreted easily and efficiently by the system.