WhatsApp will let users change playback speed of voice messages in future WhatsApp will let users change playback speed of voice messages in future The latest feature that WhatsApp was spotted testing is the ability to change the playback speed of voice messages. advertisement HIGHLIGHTS WhatsApp is testing a bunch of new features to enhance the user experience. The latest feature that WhatsApp was spotted testing is the ability to change the playback speed of voice messages. The feature like many other features is still under development. WhatsApp is testing a bunch of new features to enhance the user experience. The latest feature that WhatsApp was spotted testing is the ability to change the playback speed of voice messages. The feature like many other features is still under development. WhatsApp is yet to make an official announcement about its upcoming features.