There was a time when Unity had 4 or 5 scripting languages… I was an asset seller there and I would have to support at least C#, JavaScript, Boo and Objective-C and my life was hell.
Interoperability between those languages was hell.
Oh and then there was/is HLSL too! Oh god…
Epic know about that, this is why they removed UnrealScript thus I believe, unless it’s something really impeccable, scripting will never happen again.