Text to Speech
Please see following applications:
Dhvani has 8 Indian Langauge Support including Malayalam. It supports unicode and has many features like automatic langauge detection, mixed language support, primitive english support, number reading logic, saving the speach file etc. More over it is Free/Libre Software with GPLv2 license. Works in GNU/Linux Systems
Subhashini by CDAC. It does not accept Unicode; accepts only ML-TTKarthika text. Also, the sound is pretty robotic.