"They never listen," one would say. "Never. You have to keep saying 'Sssh.
Look at me. I'm talking. If you don't listen to what I'm saying you won't know what to do'."
"And then they don't do it," the other would chime in. "You say, 'We're going to do art now' and they just say, 'Oh, that's boring. I'm not doing that'.
"They're so rude! One of them said to me today, 'Go and get my lunchbox'!
"And they can't wait. When you're doing face painting they all push in."
"They're definitely getting worse," said my elder daughter, a veteran of the camp. "At least last year they'd sing."
"Sing?" I said, ears pricking up. As an education reporter I'm well used to complaints about children's behaviour today, but this was a new one.
"Yes, sing. We're supposed to do a talent show at the end of the week. Each group's meant to do a song. You know, for the parents to come and watch.
"I tried to teach them 'if all the raindrops were lemon drops and bubblegum'. Last year they loved it. This lot said 'no way'. I said, 'Okay, what do you want to sing?' And they said they didn't know any songs. They said singing was stupid. They said they didn't like it and they weren't going to do it and that was that."
"So what do they like?"
"Videos and computer games."
In silence we contemplated a songless childhood dominated by electronic screens. Then my younger daughter stirred. "We used to love singing at camp, do you remember?"
And suddenly they were off, dredging up the whole litany of songs they had learned at their American summer camps, many silly, a few rude, some teeth-clenchingly annoying ('I know a song that never ends it goes on and on, my friend').
We remembered tapes we had played in the car, and songs they had sung at Brownies, and how they used to drive back from school matches with the minibus stereo blaring out We Are The Champions.
We'd never been the kind of family to sit around a campfire singing Kumbaya, but songs had nevertheless been part of their lives for as long as they could remember.
Songs had bonded them with friends and classmates, helped them develop a sense of fun and language and stories, and opened them up to playing instruments, and enjoying all kinds of music, from rap to garage.
I've no doubt that, as they get older, they'll come around to Mozart and Handel, and that their lives will be richer because of all this.
"How can you say you know no songs?" asked my daughter, in genuine bafflement.
People have always sung. It's part of being human. They've whistled as they worked and sung the blues to assuage the pain of enslavement. But all that could fade.
If children become so hooked on electronic entertainment that they arrive in school unversed in the simple joys of belting out Ten Green Bottles, music could easily become something just to be consumed, not taken part in.
Which is why we all need to throw our support behind Marc Jaffrey, the leader of the Government's music task force, when he calls for more whole-school sing-ing. Because, on this score, it's much later than we realise - because singing isn't just singing, it's participating.
It's yielding yourself up to rhythm and melody and seeing yourself as part of a bigger whole. It's releasing endorphins and occasionally touching something almost transcendental - or, of course, merely standing on stage and wriggling your way through The Wheels on the Bus to please your mum.
Whatever form it takes, though, singing is a life force that connects us to ourselves and to each other and, if it isn't happening at home, schools need to make sure it happens there. Because, without it, children will always be the poorer, no matter how many computer games and DVDs they may possess.