This paper presents Deep Speech 2, an end-to-end deep learning system for automatic speech recognition that works across vastly different languages (English and Mandarin). It replaces traditional hand-engineered ASR pipelines with neural networks, achieving human-competitive transcription accuracy on standard datasets. The system uses HPC techniques for 7x speedup, enabling faster experimentation. Key innovations include Batch Normalization for RNNs, curriculum learning (SortaGrad), and GPU deployment optimization (Batch Dispatch). The approach demonstrates that end-to-end learning can handle diverse speech conditions including noise, accents, and different languages, representing a significant step toward universal speech recognition systems.
We show that an end-to-end deep learning approach can be used to recognize either English or Mandarin Chinese speech—two vastly different languages. Because it replaces entire pipelines of hand-engineered components with neural networks, end-to-end learning allows us to handle a diverse variety of speech including noisy environments, accents and different languages. Key to our approach is our application of HPC techniques, resulting in a 7x speedup over our previous system [26]. Because of this efficiency, experiments that previously took weeks now run in days. This enables us to iterate more quickly to identify superior architectures and algorithms. As a result, in several cases, our system is competitive with the transcription of human workers when benchmarked on standard datasets. Finally, using a technique called Batch Dispatch with GPUs in the data center, we show that our system can be inexpensively deployed in an online setting, delivering low latency when serving users at scale.
