DD who is 3 and a half has started saying to her 1 year old sister ' I will kill you. I will damage you.' First few times it happened, DH and I were shocked and trying not to laugh as it sounded so weird from our little girl. Not sure where she picked it up from...pretty sure I don't say 'oh I could just kill you' or anything like that when annoyed (although wouldn't want to bet on it...) and cbeebies seems unlikely as a source! Possibly some of the older boys at her nursery who she has told me say nasty things to her sometimes.
Anyway, I'm not sure how to approach it. I have told her off and explained why its a particularly nasty thing to say. She's not violent to her sister (pushing and poking is about as bad as it gets). She went through a stage of saying loudly 'I don't like anyone [or insert name of whichever child she was playing with]' which she grew out of...so maybe she'll grow out of this? It just sounds so horrible and to be honest is embarrassing me...and making me worry a bit about negative thoughts towards her sister, although they mostly play very well together. Anyone have similar experience or advice? I don't know any other kids her age that are saying this kind of thing.