Welcome to this special section of the IEEE Transactionson Computers (TC) on emergent systems, algorithms, and architectures for speech-based human-machine interaction. Recently, we have witnessed significant progress on software and hardware techniques for human-machine interaction, especially for speech-based ones. While highly successful at the core, with many commercial applications resulting from this progress, the techniques still require a great deal of improvement, especially in the areas of speech signal processing, robustness of speech systems, speech modeling, learning algorithms, real-time decoding algorithms, speech quality enhancement, speech synthesis, speaker identification, speech source separation, and so on, to further impact speech-centric human-machine interaction. This special section concentrates on the state-of-the art of such techniques. We received many submissions for consideration. We finally selected nine papers among them, which have been critically peer-reviewed with top-quality research and/or with more timely information than the papers that were not selected. The selected papers have addressed a considerable number of new ideas and applications in the field of speech-based human-machine interaction.