Absolute.
Bullsh*t.
Can you limit their size, stunt their growth? Sure. Oh but didn't we mention? The turtles internal organs don't slow growth at the same pace, and their development will be hindered, effectively destroying the long-term ability to process nutrients and waste properly, significantly shortening their life and altering their "mood" and activity levels in the meantime. In reality, a small enclosure hardly ever (if, in fact, ever) stunts growth to a noticeable degree. What usually happens is the water quality becomes so bad that the turtle ends up dying before any real stunting might happen. The only way to avoid this is to have absolutely insane amounts of filtration for the amount of water you have, or to do an absolutely insane amount of water changes. (EDIT: or just get an acceptable enclosure)
As far as learning their names... turtles are rarely responsive to anything other than mating opportunities, territorial aggression, or food. My turtles know that I mean them when I say ''turtle'', probably because I usually say this when I'm doing something they don't like (like handling them or cleaning their enclosure, or just getting too close for comfort) or when it's feeding time. If you can get one to respond to a name or term for any other reasons, I'd be impressed as hell.
Josh H