OsmAnd+ Voice Navigation Not Working
I had the same problem (I think) with the play store Osmand 3.5.5 and android 8.1. Here's what I did:


wait for Osmand 3.6 to be released.
start a new route
go to options -> Navigation settings
tap on "voice prompts" even though it is already "on". Tap on the text not the switch!
You can see a bunch of options now such as "voice guidance" which maybe defaults to "Don't use". Make sure it is set to some language.