Let me give you some examples.
A nice picture that I showed her. She said "That's sick mum". Now to me, that means it is horrible/depraved/unwell. No, apparently this now means it's it 'nice'. So when I am sick, am I fine? What do I say to the doctor now? Oh dear, this is getting very confusing.
I am off to collect her and give her a time I'll be there. "Cool beans" she says. I understand this means "that's great, thanks mum". This must be due to a slightly 60's/70's throwback in my mind that I 'get' this.
I have seen parents referred to as "rents". I have no idea at all what this means! I am assuming it has something to do with living in their house for free.
My friends son said my driving was "beast". Had I scared him? Was I too fast/slow? No, apparently this means that I can "drive really well". Excellent. I am beast. I'll remember that.
My friend has bought a new (to her) car and her daughter said "Boom". Some scratching of head ensued until my friend confirmed that boom meant 'fantastic'.
I'm getting rather scared to talk to my teen in case I say something bad without meaning it or, worse still, find I am suddenly promising her something like money or taxi services unintentionally! 'Nuff' said.
Google do a fairly good job with their foreign language translators but I wonder if they have considered the challenge of "Teen Speak"? I'm sure it would be easier if we all learned Klingon ;-)