Word recordings: Yue Tan (Université de Caen, Shtooka), via hugolpz/audio-cmn.
Source: https://github.com/hugolpz/audio-cmn (commit ff9ed3d0c631195bd2c06f39450f3264c7124040, folder 64k/hsk).
License: CC BY-SA 3.0 US, https://creativecommons.org/licenses/by-sa/3.0/us/

Syllable recordings (s/): Chen Wang, via hugolpz/audio-cmn.
Source: https://github.com/hugolpz/audio-cmn (commit ff9ed3d0c631195bd2c06f39450f3264c7124040, folder 64k/syllabs).
License: CC BY-SA (version not stated by the source), as stated in the source's README

Each file is copied unchanged and renamed to its word id or syllable. Unmodified clips
beside the site code form a collection; the license does not extend to the code.