My article “Machine-Based Decoding of Human Voices and Speech” has been published in “The Oxford Handbook of Voice Perception“, edited by S.Fruholz and P.Belin. The chapter provides a general introduction to the main approaches aimed at speech recognition and inference of speech-based social perceptions. After showing that our very physiology is shaped around the perception of human voices, the chapter shows that speech is probably the signal most common studied and analysed in the technological literature. Furthermore, the chapter introduces the main approaches adopted to automatically transcribe speech signals (a task called speech recognition) and to infer from them different types of traits and psychological phenomena (personality, emotions, etc.).