mother tongue

So what do your kids accents sound like?? Jess even though she's not from the US (she's only been in the states 2 twice and too young to remember) she has a very Strong US accent more pronounced than mine. Since the introduction of Cartoon Network she seems to have acquired a Blossom/Bubbles Powerpuff girl Twang. My American accent isn't that strong anymore. When we went to Paris on holiday Jess tried to say Au revoir and it sounded like "Rachel" off of friends.

Philip isn't talking yet, but a couple moved to the US with us this winter in the job transfer that brought us here. (does that make sense?) Anyway, they have thick northern accents - as does their 3 year old son - but the son has been in day care twice a week now for a month and he is noticeably changing his accent! A lot of terms (diapers instead of nappies etc), but also just the accent.

In England my in-laws live right near a US Air Force base. They were selling their home at one point and I met a lot of US military families with kids. I thought it was so funny that when the kids were talking to my family they sounded English, but when they were talking to their parents (or even me) they sounded American! Very adaptable indeed.

Anyway, they have thick northern accents - as does their 3 year old son -

'Thick', to me, means 'stupid'.
I hope that's not what you meant! 

thick as in Heavy sounding not a judgement on their intellect 

My daughter has a strange hybrid accent but mostly American.  She drawls like a true Texan.  I have no idea where she gets it from.  She is starting sound more British and I think it will stop when she goes to school next year.

My son hasn't a trace of American in his accent, only his word choice.

'Thick', to me, means 'stupid'.
I hope that's not what you meant!

Of course that isn't what I meant.

I knew what you meant. 

My 6 month old can't talk yet but he loves to immitate his dad's smoker's cough. I was on the train with him one day when he did it and I said "Now Ethan, it's time you gave up smoking" and everyone in the carriage gave me the dirtiest looks.