Thread:Project:Support desk/Deactivate "Talk"/reply (3)

Above line would disable creation of talk pages for anonymous users. However, I don't know, if that is enough: Users, who are logged in, might still have permission to create talk pages so that you might want to adjust their permissions as well.

Another aspect is that the tab "Talk" next to the tab "Article" will still be displayed although it is useless. You might want to hide it using CSS.