There is a nice demo program released for Hindi (can be extended for Indic languages as well) speech to text conversion. Now you simply need to speak in a microphone and record your word directly in Unicode Hindi text. Alternately, you can give oral commands in Hindi to do computing tasks like “Thunderbird Kholo” to open thunderbird.
This Hindi speech recognition program is currently available for Linux as it is based on Sphinx and Perl. Still, a port to windows is possible in near future. The project is currently maintained by Sachin Joshi as a part of Sarai FOSS project.
Download Hindi Automatic Speech Recognition System from here