There are plenty of languages available. WML is a very compact XML based language where actual content and the rendering of that content is mostly left for the terminal to decide. Therefore WML saves the valuable over the air bandwith. However, since new mark up languages will appear you should design your applications in a way that it is not strictly tied to a specific mark up language or screen size, but instead it could be easily adapted to new ones as they appear. For example the data could be stored in XML format from which different mark up languages can be generated. Now it is time concentrate on WAP1.2.1 and WML using GPRS bearer, but keep in mind that XHTML is coming in the future.