Fish can't talk, dummy.

Yesterday Sawyer was pretending he had a fish tank with little fish in it.  He was telling my father about the fish, and as he was doing this my father leaned over to speak to the fish in hopes of playing along in Sawyer's pretend world.  Sawyer was not having this.  S told my father, "I don't know that fish can talk."  He should have added "dummy" or "idiot" at the end of the sentence because his tone expressed this condescending manner.  I suppose even a two and a half year old realizes the limitations of imagination, or maybe this particular fish could not talk in Sawyer's pretend world.