This book constitutes the refereed proceedings of the 19th National Conference on Man-Machine Speech Communication, NCMMSC 2024, held in Urumqi, China, during August 15–18, 2024.The 33 papers included in these proceedings were carefully reviewed and selected from 205 submissions. They deal with topics such as speech technology and large language models, audio processing, prosody modeling and dialogue systems. Key areas include speech recognition, speaker identification and verification, speech/sound/music synthesis, speech enhancement, sound event detection, multimodal systems, conversational AI, phonetics, phonology and prosody analysis, auditory processing, and acoustic scene modeling etc.