Actually they don't.
We've had our two kittens since the end of May, they've settled in perfectly, sit on command, come when they want to called. They're fairly affectionate (on their own terms) one loves to be held like a baby and the other licks your hand when he's feeling the love. But neither of them meeow! Ever. They purr, one of them will give a pathetic squeak that is almost a meeow when they're starving and you're putting out their food and taking your time, and the other makes some odd grunt like noises when playing. But general conversational meowing - it never happens.
The cats we had before would meeow if you looked at them, but I can't remember whether they meowed when they were kittens or not. Is it something they might grow into, should I start meeowing at them to encourage them?