TAL was developed internally within the 大象传媒 as a way of vastly simplifying TV application development whilst increasing the reach of 大象传媒 TV applications such as iPlayer. Today all of the 大象传媒's HTML-based TV applications are built using TAL.
There are hundreds of different devices in the marketplace and they all use slightly different technologies to achieve the same result. The purpose of TAL is to allow you to write an application once, and be confident that it can be deployed to all HTML-based TV devices.