What is Text Services Framework?
Text Services Framework (TSF) is a device-independent, language-neutral, and extensible system for text input and language technologies.
TSF-enabled applications can receive text input from any text service that supports TSF without having to be aware of any details of the text source.
Text services supply text to applications in a way that does not require any detailed knowledge of the applications that produce or receive the text. For example, a text service can provide text input from speech or handwriting input devices.