If it's the first time that James has heard a raised voice and a profanity in the car, then either Daddy is a saint or Mummy is a genius at map-reading. We know instinctively that children will imitate our speech and as responsible parents we should set an example, but it's not always that easy.

First, how to explain the expletive itself? If James starts to chant it from the back, the most effective strategy is to pretend that it's one of Daddy's silly, made-up words and look disinterested, however horrifying it may sound from the mouth of an innocent six-year-old. “I wouldn't draw attention to the word itself,” says Elizabeth Darke, a psychologist and positive-parenting expert. “You shouldn't attach more importance to it than it deserves.”

You can distract yourself with the notion that swear words aren't inherently offensive. It's society that decides what we view as profane, says Tony McEnery, professor of linguistics at Lancaster University and author of Swearing in English: Bad Language, Purity and Power from 1586 to the Present. “Words shift in their acceptability - ‘my God' isn't viewed as badly as it used to be; racist terms now are, especially among younger people.”

There are points in a child's development when they'll be a lot more aware of what is socially taboo. During nursery and early primary school, they find anything to do with excretion excruciatingly hilarious. In early adolescence, coarser language is part of peer culture.

Ask your father: why do some people have white skin?

The simple answer is melanin, but it's important to know why your child has asked the question, says Emma Cook

Background

• Ask Your Father: why haven't I got a brother or sister?

• How come Daddy can't work the washing machine?

• Ask your father: why aren't you married to daddy?

• Ask your father: why are you on a diet?

• Ask Your Father: What's the biggest number in the world?

Meanwhile, if James is more upset at the idea that Daddy has lost his temper, then it's best to explain that sometimes we all get cross and say words that don't sound very nice. This could be an opportunity for a more general discussion about what language is acceptable, Darke advises.

“You could think of substitutes for both parents and children to stick to; like ‘gosh' or ‘golly' instead of ‘God' or 'be quiet' instead of ‘shut up', and as soon as they use the appropriate word jump on that chance to praise them.” And Daddy too, if he ever manages a Zen-like “Be quiet, please”, the next time you're lost and James is screaming for the loo.EMMA COOK

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