Well, as you've probably surmised by this point, Roblox now has voice chat which was just released out of beta -- "Spatial voice chat," to be specific.

How do you make games in Roblox? Firstly you'll need to download and install Roblox Studio, a free piece of software that is used to create all Roblox games.

Voice chat arrives in Roblox - here's everything you need to know about Spatial Voice.