Also keep in mind that you can remove chat channels from chat tabs, pretty much customize what you see. In theory, you can make it as difficult as possible to see chat outside of one's local area if abuse from these sources is a problem.
Sadly, abuse can happen anywhere and at any time via almost any avenue. There's no substitute for supervision.
The best way to supervise, IMHO, is to have two accounts/PCs and play together, helping each other out.
No need for chat software/headphones if you're next to each other at home etc.