How Do We Measure Speech Quality?

The way we measure speech quality primarily is called word error rate or WER for sure. For certain use cases on the Google Assistant, especially Assistant voice typing, we can get word error rate down to 4%, which is basically as good as humans can do. And it's really important because as we've seen throughout Google, as we're able to build higher quality speech models, more product possibilities exist. So somehow when it comes to voice, have super high expectations that you need to live up to somehow.