Besides their infrasounds moving along on concrete or rock? Two times in my life I have been surprized by a turtle...once as a child I went out my front door and there in the middle of the street, no cars anywhere - was walking along a very very large turtle!
early this month, sitting outside with a neighbor - happenstancely both there at the same time with our coffee in hand and waking up in mind, I turned and saw a turtle approaching!
As it turns out - the turtle (actually tortoise) went out its keeper's door, walked along the walkway til it got to the many stairs which it successfully descended, made its further way to the parking lot, actually traversed the large parking lot and then came walking into our courtyard...
So, do turtles ever vocalize?