Visual Voicemail coming to some carriers with Android M
Visual voicemail allows the user to see a list of phone numbers that messages were left from. It allows you to delete messages or listen to them without having to listen to those annoying verbal directions. The OG Apple iPhone, back in 2007, was the first handset to offer Visual Voicemail.
The ticket in the issue tracker also shows that Google plans on transcribing the messages, although this will be up to each carrier to support. If a carrier decides to support VVM transcriptions, it will be seen in the dialer. However, no carrier is working on that feature at the moment.
source: AndroidDeveloperPreview via AndroidPolice, AndroidandMe