Disclosed herein is a GPU-accelerated speech recognition engine optimized for faster than real time speech recognition on a scalable server-client heterogeneous CPU-GPU architecture, which is specifically optimized to simultaneously decode multiple users in real-time. In order to efficiently support real-time speech recognition for multiple users, a “producer/consumer” design pattern is applied to decouple speech processes that run at different rates in order to handle multiple processes at the same time. Furthermore, the speech recognition process is divided into multiple consumers in order to maximize hardware utilization. As a result, the platform architecture is able to process more than 45 real-time audio streams with an average latency of less than 0.3 seconds using one-million-word vocabulary language models.