In WhatsApp , the function to modify the playback speed of received voice notes is already available, both for Android and iOS.
Before an audio, the user has the option of listening to it at normal speed or accelerated to 50% or 100%.
To the left or right of the playback line, depending on whether the audio is sent or received, an indicator with the number 1.0X appears indicating that the message runs at the speed that it was recorded. To increase the playback speed, just press that number which will immediately indicate 1.5X (which increases the speed to 50%) and if we press again it will go to 2.0X, increasing to twice the normal speed. It only remains to click on these numbers again to go through the options and choose the most convenient at that time.
Ideal and practical for those users with little time or who prefer to quickly get the main idea that is communicated through the voice message.