As suggested on to do page of quiz extension, sound clips can be used for assessment.
The upload from browser feature isn't completed yet.
More information about microphone upload over here
2018 version: https://www.youtube.com/watch?v=Bof5sJWZ100&t=103s
2017 paper: https://arxiv.org/pdf/1709.01713.pdf
2018 blueprint: https://www.ets.org/Media/Research/pdf/RM-18-02.pdf
2020 multi-phrasal version: https://www.amiralearning.com/