The article focuses on various multimodal interfaces. During multimodal communication, one speaks, shifts eye gaze, gesture and moves in a powerful flow of communication that bears little resemblance to the discrete keyboard and mouse clicks entered sequentially with a graphical user interface. A profound shift is now occurring toward embracing users' natural behavior as the center of the human-computer interface. Multimodal interfaces are being developed that permit highly skilled and coordinated communicative behavior to control system interactions in a more transparent experience than ever before. Human voice, hands and the entire body, once augmented by sensors such as microphones and cameras, are becoming the ultimate transparent and mobile multimodal input devices. The area of multimodal systems has expanded rapidly during the past five years. State-of-the art multimodal speech and gesture systems now process complex gestural input other than pointing, and new systems have been extended to process different mode combinations