VOIP does not work in networked projects. This was tested in QAGame and ShooterGame. We made sure to enable Voice in both the BaseEngine and DefaultEngine (in both projects). Ducking appears to work, as audio will dim when pushing down the talk key. But other players cannot hear someone talk.
Requires two users to test
The other player won't hear the player talk.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-31605 in the post.