It has recently become feasible to run personal digital assistants on phones
and other personal devices. In this paper we describe a design for a natural
language understanding system that runs on device. In comparison to a
server-based assistant, this system is more private, more reliable, faster,
more expressive, and more accurate. We describe what led to key choices about
architecture and technologies. For example, some approaches in the dialog
systems literature are difficult to maintain over time in a deployment setting.
We hope that sharing learnings from our practical experiences may help inform
future work in the research community.

近期，手机和其他个人设备上运行个人数字助手成为可能。本文描述了在设备上运行的自然语言理解系统的设计。与基于服务器的助手相比，该系统更具隐私性、可靠性、速度更快、表达能力更强且更准确。我们描述了关于架构和技术的关键选择。例如，对话系统文献中的一些方法在部署环境中难以长期维护。希望通过分享我们的实践经验，能够为未来的研究工作提供有益信息。