Are Border Terriers vocal

No, only when they think someone is one their territory or something. Mine barks at people walking on the sidewalk or when she hears a doorbell on tv. When she sees people on the sidewalk she only barks, she never attacked anyone in the three years she lived with us. But, I do warn you, Rat Terriers pick one person to be their owner. They are still friendly to everyone they meet, they just like that one person more.