Minecraft version :
1.12.2
Defiled Lands version :
defiledlands-1.12.2-1.4.1

I keep a few book wyms near my main area of work and they constantly hiss loudly, it has gotten to the point where I want to put them deep underground so I never have to hear the sound again. An option to reduce how often the sound plays and the volume of the hissing sound would be fantastic.

Will simply reduce their sound volume to a more acceptable level, and see if there's a way to make them make sounds less often.

As a workaround to anyone else: Turning off the friendly mob sounds in your settings silences them.

72c9fe0 should fix it for next update. Issue will be closed once update is live (may be a small hotfix or change a few more things).