My 2 and a half year old must have supersonic hearing. Realising Lila's penchant for imitation after coming home with the f* word at 18 months after going to the football with Mat we have been really careful with our language. Still, its not hard when she talks to spot the bad parenting:

to her doll after she has just given it a bath - "I am just so damn happy" (probably me)
to just about any request we make of her (add very aggressive tone) 'NO, OK, do you understand?" (me again, about 2000% less aggressive than the way she says it)
when trying to cut a story short she is familiar with "daddy, concentrate" (Mat)
when we tell her its bedtime "no, just 5 more minutes", no lila, its bedtime now so you have the choice of which book you want to read "no mummy, shut up" (thanks shrek)
in the line at the supermarket 'mummy, we don't need all that. lila just get chocolate' (me again, when talking on the phone to Mat)
again, in line at the supermarket (at the top of her voice) 'mummy, where is my baby brother?'. I was so distracted with Millie fussing & gettign the shopping onto the conveyor belt and it sounded so urgent for while there i started looking for him until i realised there is no brother, we don't have a boy. lila sounded so convincing the checkout lady offered twice to have someone go look for my missing son.